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Index

<hr>

<h2 id="index">Index</h2>

<li>abort (<code>→</code>) [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>absolute value [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>]</li>

<li>active workspace [<a href="chapter4.html">1</a>, <a href="chapter4.html#section-4.2-the-active-workspace">2</a>, <a href="chapter4.html#listing-the-contents-of-the-active-workspace-nms-fns-ops-vars">3</a>]

<ul>

<li>adding to [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]</li>

<li>changing name of [<a href="chapter4.html#name-of-the-active-workspace">1</a>]</li>

<li>contents of [<a href="chapter4.html#listing-the-contents-of-the-active-workspace-nms-fns-ops-vars">1</a>]</li>

<li>removing objects from [<a href="chapter4.html#removing-objects-from-the-active-workspace-erase">1</a>]</li>

<li>replacing contents of [<a href="chapter4.html#replacing-the-contents-of-the-active-workspace">1</a>]</li>

</ul></li>

<li>add a set of numbers [<a href="chapter1.html#adding-up-numbers">1</a>]</li>

<li>addition (<code>+</code>) [<a href="chapter1.html#simple-arithmetic">1</a>, <a href="chapter1.html#adding-up-numbers">2</a>]</li>

<li>addition of exponents [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>addition-reduction (<code>+/</code>) [<a href="chapter1.html#adding-up-numbers">1</a>]</li>

<li>alphabet

<ul>

<li>for names [<a href="chapter1.html#names">1</a>]</li>

</ul></li>

<li><span class="small-caps">APL</span> keyboard [<a href="chapter1.html">1</a>, <a href="appendixE.html">2</a>]</li>

<ul>

<li>active workspace [<a href="chapter4.html#section-4.2-the-active-workspace">1</a>]</li>

<li>function [<a href="chapter1.html#simple-arithmetic">1</a>, <a href="chapter1.html#functions">2</a>]</li>

<li>libraries [<a href="chapter4.html#section-4.1-libraries">1</a>]</li>

<li>operator [<a href="chapter1.html#adding-up-numbers">1</a>, <a href="chapter1.html#operators">2</a>]</li>

</ul></li>

<li><span class="small-caps">APL</span> operator [<a href="chapter1.html#adding-up-numbers">1</a>]</li>

<li>arccos [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arccosh [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arc cosine [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arc cosine hyperbolic [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arcsine [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arc sine hyperbolic [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arcsinh [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arctan [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arc tangent [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arc tangent hyperbolic [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arctanh [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>arguments of a function [<a href="chapter1.html#functions">1</a>]

<ul>

<li>conformability with scalar functions [<a href="chapter2.html#scalar-conformability-and-scalar-extension">1</a>]</li>

<li>placement of for dyadic functions [<a href="chapter1.html#functions">1</a>]</li>

<li>placement of for monadic functions [<a href="chapter1.html#functions">1</a>]</li>

</ul></li>

<li>arithmetic [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

<li>arithmetic progression [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

<li>array processing

<ul>

<li>feature of <span class="small-caps">APL</span> [<a href="chapter1.html#vector-notation">1</a>]</li>

</ul></li>

<li>arrays

<ul>

<li>applying a function to [<a href="chapter1.html#thinking-arrays">1</a>]</li>

<li>applying scalar functions to [<a href="chapter2.html#scalar-conformability-and-scalar-extension">1</a>, <a href="chapter5.html#scalar-functions">2</a>]</li>

<li>classes of [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>columns of [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>count [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>, <a href="chapter5.html#count">2</a>]</li>

<li>defined [<a href="chapter1.html">1</a>, <a href="chapter1.html#terms-for-data">2</a>, <a href="chapter5.html#section-5.1-properties-of-arrays">3</a>]</li>

<li>depth of [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>, <a href="chapter5.html#depth">2</a>]</li>

<li>display of [<a href="chapter5.html#reshape">1</a>]</li>

<li>index of [<a href="chapter6.html#indexing">1</a>]</li>

<li>intersection of [<a href="chapter6.html#without">1</a>]</li>

<li>items [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>manipulating along an axis [<a href="chapter5.html#section-5.5-manipulating-an-array-along-an-axis">1</a>]</li>

<li>matrix [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>nested [<a href="chapter1.html#terms-for-data">1</a>, <a href="chapter2.html#scalar-functions-and-nested-arrays">2</a>, <a href="chapter5.html#section-5.1-properties-of-arrays">3</a>]</li>

<li>prototype of [<a href="chapter5.html#first">1</a>]</li>

<li>scalar [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>search for items using index of [<a href="chapter6.html#index-of">1</a>]</li>

<li>selecting a subset [<a href="chapter6.html#section-6.2-selecting-subsets-of-arrays">1</a>]</li>

<li>shape of [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>simple [<a href="chapter1.html#terms-for-data">1</a>, <a href="chapter5.html#section-5.1-properties-of-arrays">2</a>]</li>

<li>sorting items in [<a href="chapter6.html#grade-up-and-grade-down">1</a>]</li>

<li>unshaping with enlist [<a href="chapter5.html#enlist">1</a>]</li>

<li>unshaping with ravel [<a href="chapter5.html#ravel">1</a>]</li>

<li>vector [<a href="chapter1.html#vector-notation">1</a>, <a href="chapter5.html#section-5.1-properties-of-arrays">2</a>]</li>

</ul></li>

<li>arrow

<ul>

<li>assignment [<a href="chapter1.html#assignment">1</a>, <a href="chapter1.html#vector-notation">2</a>, <a href="chapter7.html#section-7.4-output-with-quad-and-quote-quad">3</a>]</li>

<li>to clear errors [<a href="chapter1.html#types-of-errors">1</a>]</li>

</ul></li>

<li>assignment [<a href="chapter1.html#assignment">1</a>, <a href="chapter1.html#vector-notation">2</a>, <a href="chapter7.html#section-7.4-output-with-quad-and-quote-quad">3</a>]

<ul>

<li>of data to a variable [<a href="chapter1.html#assignment">1</a>]</li>

<li>selective [<a href="chapter2.html#replacing-items-in-a-vector-selective-assignment">1</a>]</li>

</ul></li>

<li>assignment arrow (<code>←</code>) [<a href="chapter1.html#assignment">1</a>]</li>

<li>associated processors [<a href="postscript.html#external-names-and-associated-processors">1</a>]</li>

<li>asterisk (<code>⋆</code>)

<ul>

<li>in state indicator [<a href="chapter4.html#seeing-the-state-indicator-sis">1</a>]</li>

<li>not used for multiplication [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

<li>power [<a href="chapter2.html#scalar-function-power">1</a>, <a href="chapter6.html#power-and-exponential">2</a>]</li>

</ul></li>

<li>attention [<a href="chapter7.html#attention">1</a>]</li>

<li>auxiliary processors [<a href="postscript.html#auxiliary-processors">1</a>]</li>

<li>average, program for [<a href="chapter3.html#defined-sequence-structure">1</a>]</li>

<li>axes of an array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>axis

<ul>

<li>adding [<a href="chapter5.html#ravel-with-axis">1</a>]</li>

<li>default [<a href="chapter5.html#section-5.5-manipulating-an-array-along-an-axis">1</a>]</li>

<li>fractional [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>length [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>manipulation of array along [<a href="chapter5.html#section-5.5-manipulating-an-array-along-an-axis">1</a>]</li>

<li>names of [<a href="chapter5.html#reshape">1</a>]</li>

<li>of an array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

</ul></li>

<li>axis specification

<ul>

<li>empty with ravel [<a href="chapter5.html#ravel-with-axis">1</a>]</li>

<li>fractional with catenate [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>with catenate [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>with disclose [<a href="chapter5.html#disclose-with-axis">1</a>]</li>

<li>with enclose [<a href="chapter5.html#enclose-with-axis">1</a>]</li>

<li>with n-wise reduction [<a href="chapter5.html#n-wise-reduction">1</a>]</li>

<li>with ravel [<a href="chapter5.html#ravel-with-axis">1</a>]</li>

<li>with reduction [<a href="chapter5.html#reduction-with-axis">1</a>]</li>

<li>with scalar functions [<a href="chapter5.html#scalar-functions-with-axis">1</a>]</li>

</ul></li>

<li>bar chart [<a href="chapter6.html#indexing">1</a>]</li>

<li>binomial (<code>!</code>) [<a href="chapter6.html#factorial-and-binomial">1</a>]</li>

<li>blank character

<ul>

<li>representation of [<a href="chapter2.html#section-2.2-character-data">1</a>]</li>

</ul></li>

<li>blanks

<ul>

<li>as padding [<a href="chapter2.html#selecting-items-from-a-vector-take">1</a>]</li>

<li>character [<a href="chapter2.html#section-2.2-character-data">1</a>]</li>

<li>in numbers [<a href="chapter1.html#numbers">1</a>]</li>

<li>redundant [<a href="chapter1.html#use-of-blanks">1</a>]</li>

<li>removing from a character vector [<a href="chapter6.html#without">1</a>]</li>

<li>separate names [<a href="chapter1.html#names">1</a>]</li>

<li>to indicate grouping [<a href="chapter1.html#thinking-arrays">1</a>]</li>

</ul></li>

<li>body

<ul>

<li>of a program [<a href="chapter3.html#program-structure">1</a>]</li>

</ul></li>

<li>Boolean functions [<a href="chapter6.html#boolean-functions">1</a>]

<ul>

<li>with reduction [<a href="chapter6.html#boolean-functions">1</a>]</li>

</ul></li>

<li>bottom-up programming [<a href="chapter8.html#building-and-maintaining-the-magazine-matrix">1</a>]</li>

<li>brackets

<ul>

<li>for axis specification [<a href="chapter5.html#section-5.5-manipulating-an-array-along-an-axis">1</a>]</li>

<li>for indexing [<a href="chapter2.html#selecting-items-from-a-vector-indexing">1</a>, <a href="chapter6.html#indexing">2</a>]</li>

</ul></li>

<li>branch (<code>→</code>)

<ul>

<li>conditional [<a href="chapter7.html#labels">1</a>]</li>

<li>escape [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>for looping [<a href="chapter7.html#more-about-unconditional-branching">1</a>]</li>

<li>niladic [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>out of range [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>to an empty vector [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>unconditional [<a href="chapter7.html#labels">1</a>]</li>

<li>without an argument [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

</ul></li>

<li>breadth-first search [<a href="chapter8.html#implementing-the-puzzle-solving-program">1</a>]</li>

<li>caret (<code>^</code>)

<ul>

<li>in error report [<a href="chapter1.html#types-of-errors">1</a>]</li>

</ul></li>

<li>catenate (<code>,</code>) [<a href="chapter2.html#joining-vectors-catenate">1</a>]

<ul>

<li>compared to vector notation [<a href="chapter2.html#catenate-versus-vector-notation">1</a>]</li>

<li>to an empty vector [<a href="chapter2.html#using-empty-vectors">1</a>]</li>

</ul></li>

<li>catenate with axis (<code>,[]</code>) [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>ceiling (<code>⌈</code>) [<a href="chapter2.html#scalar-functions-floor-and-ceiling">1</a>]</li>

<li>character data [<a href="chapter2.html#section-2.2-character-data">1</a>]

<ul>

<li>as argument to a function [<a href="chapter2.html#functions-that-work-on-characters">1</a>]</li>

<li>converted to numbers [<a href="chapter6.html#index-of">1</a>]</li>

<li>converted to numeric [<a href="chapter7.html#executing-character-input">1</a>]</li>

<li>in a vector with numeric data [<a href="chapter2.html#vectors-with-both-numbers-and-characters">1</a>]</li>

<li>input [<a href="chapter7.html#character-input">1</a>]</li>

<li>with equal [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>with not equal [<a href="chapter6.html#relational-functions">1</a>]</li>

</ul></li>

<li>character input after output</li>

<li>character input (<code>⍞</code>) [<a href="chapter7.html#character-input">1</a>]</li>

<li>character set [<a href="appendixE.html">1</a>]</li>

<li>character string [<a href="chapter2.html#section-2.2-character-data">1</a>, <a href="chapter7.html#character-input">2</a>]</li>

<li>character vectors [<a href="chapter2.html#character-vectors">1</a>, <a href="chapter7.html#character-input">2</a>]

<ul>

<li>effect of parentheses on [<a href="chapter2.html#character-vectors">1</a>]</li>

</ul></li>

<li>circle (<code>○</code>) [<a href="chapter6.html#trigonometric-functions">1</a>]</li>

<li>classes of arrays [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li><code>)CLEAR</code> [<a href="chapter4.html#section-4.2-the-active-workspace">1</a>]</li>

<li><code>CLEAR WS</code> [<a href="chapter4.html#section-4.2-the-active-workspace">1</a>]</li>

<li>closed formula [<a href="chapter7.html#closed-formula">1</a>]</li>

<li>columns of an array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>comma (<code>,</code>) [<a href="chapter1.html#numbers">1</a>]

<ul>

<li>not used to separate groups of digits [<a href="chapter1.html#numbers">1</a>]</li>

<li>symbol for catenate [<a href="chapter2.html#joining-vectors-catenate">1</a>]</li>

<li>symbol for ravel [<a href="chapter5.html#ravel">1</a>]</li>

</ul></li>

<li>command [<a href="appendixB.html#selecting-an-editor">1</a>]

<ul>

<li><code>)CLEAR</code> [<a href="chapter4.html#section-4.2-the-active-workspace">1</a>]</li>

<li><code>)EDITOR</code> [<a href="appendixB.html#selecting-an-editor">1</a>]</li>

<li><code>)ERASE</code> [<a href="chapter4.html#removing-objects-from-the-active-workspace-erase">1</a>]</li>

<li><code>)PCOPY</code> [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]</li>

</ul></li>

<li>comments (<code>⍝</code>) [<a href="chapter3.html#defined-function-structure">1</a>, <a href="chapter3.html#comments">2</a>, <a href="chapter3.html#good-apl2-programming-practices">3</a>]</li>

<li>common logarithm (<code>⍟</code>) [<a href="chapter6.html#logarithm">1</a>]</li>

<li>comparison tolerance [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>complex conjugate [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>complex number

<ul>

<li>conjugate of [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>imaginary part [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>phase [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>representation of [<a href="chapter6.html#power-and-exponential">1</a>]</li>

</ul></li>

<li>complex numbers [<a href="postscript.html#complex-numbers">1</a>]</li>

<li>compress (<code>/</code>)

<ul>

<li>See replicate</li>

</ul></li>

<li>conditional branch [<a href="chapter7.html#labels">1</a>]</li>

<li>conformability of scalar function

<ul>

<li>dyadic [<a href="chapter2.html#scalar-conformability-and-scalar-extension">1</a>]</li>

<li>monadic [<a href="chapter2.html#scalar-conformability-and-scalar-extension">1</a>]</li>

</ul></li>

<li>conjugate of a complex number [<a href="chapter6.html#circular-functions">1</a>]</li>

<li><code>CONTINUE</code>

<ul>

</ul></li>

<li><code>CONTINUE</code> workspace [<a href="chapter4.html">1</a>]

<ul>

<li>dangers of using [<a href="chapter4.html#more-about-the-workspace-continue">1</a>]</li>

<li>features of [<a href="chapter4.html#more-about-the-workspace-continue">1</a>]</li>

</ul></li>

<li>control structures [<a href="chapter7.html#section-7.6-control-of-execution-iteration">1</a>]</li>

<li>converting characters to numbers [<a href="chapter7.html#executing-character-input">1</a>]</li>

<li><code>)COPY</code> [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]

<ul>

<li>protected [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]</li>

</ul></li>

<li>cosine [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>cosine hyperbolic [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>count of an array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>, <a href="chapter5.html#count">2</a>]</li>

<li>cube roots [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>data

<ul>

<li>character [<a href="chapter2.html#section-2.2-character-data">1</a>]</li>

<li>collected in an array [<a href="chapter1.html#terms-for-data">1</a>]</li>

<li>grouping of for computation [<a href="chapter1.html#thinking-arrays">1</a>]</li>

<li>selecting from an array

<ul>

<li>with first (<code>↑</code>) [<a href="chapter2.html#selecting-items-from-a-vector-first">1</a>]</li>

<li>with index (<code>[]</code>) [<a href="chapter2.html#selecting-items-from-a-vector-indexing">1</a>]</li>

</ul></li>

<li>selecting repeatedly [<a href="chapter2.html#selecting-items-from-a-vector-indexing">1</a>]</li>

<li>terms for [<a href="chapter1.html#terms-for-data">1</a>]</li>

</ul></li>

<li>debugging your program [<a href="chapter7.html#section-7.2-debugging-your-program">1</a>]</li>

<li>decimal point [<a href="chapter1.html#numbers">1</a>]</li>

<li>decode (<code>⊥</code>) [<a href="chapter6.html#decode">1</a>]</li>

<li>default

<ul>

<li>order of execution [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

</ul></li>

<li>defined function [<a href="chapter3.html#section-3.2-programs-remember-expressions">1</a>, <a href="chapter3.html#defined-function-structure">2</a>]</li>

<li>defined operator [<a href="chapter3.html#defined-operator-structure">1</a>]</li>

<li>defined sequence [<a href="chapter3.html#section-3.2-programs-remember-expressions">1</a>, <a href="chapter3.html#defined-sequence-structure">2</a>]</li>

<li>definition mode [<a href="chapter3.html#defining-a-program">1</a>, <a href="chapter3.html#using-defined-functions-operators-and-sequences">2</a>]</li>

<li>depth (<code>≡</code>)

<ul>

<li>increased by enclose [<a href="chapter5.html#nested-reshaping-of-an-array-enclose">1</a>]</li>

<li>of an array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>, <a href="chapter5.html#depth">2</a>]</li>

<li>of a nested array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>of a simple array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>of a simple scalar [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

</ul></li>

<li>derived functions [<a href="chapter1.html#operators">1</a>]

<ul>

<li>names of [<a href="chapter3.html#naming-derived-functions">1</a>]</li>

</ul></li>

<li>direction (<code>×</code>) [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>]

<ul>

<li>relationship to magnitude (<code>∣</code>) [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>]</li>

</ul></li>

<li>disclose (<code>⊃</code>) [<a href="chapter5.html#nested-reshaping-of-an-array-disclose">1</a>]

<ul>

<li>relationship to enclose (<code>⊂</code>) [<a href="chapter5.html#nested-reshaping-of-an-array-disclose">1</a>]</li>

</ul></li>

<li>disclose with axis (<code>⊃[]</code>) [<a href="chapter5.html#disclose-with-axis">1</a>]</li>

<li>display

<ul>

<li>of arrays [<a href="chapter5.html#reshape">1</a>]</li>

<li>of numbers [<a href="chapter1.html#numbers">1</a>]</li>

</ul></li>

<li><code>DISPLAY</code> function [<a href="chapter1.html#display-function">1</a>, <a href="chapter5.html#applying-the-display-function-to-arrays">2</a>]

<ul>

<li>summary [<a href="chapter5.html#applying-the-display-function-to-arrays">1</a>]</li>

</ul></li>

<li>division (<code>÷</code>) [<a href="chapter1.html#simple-arithmetic">1</a>]

<ul>

<li>alternate symbols not allowed [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

</ul></li>

<li><code>DOMAIN ERROR</code> [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li>domino [<a href="chapter6.html#matrix-inverse">1</a>]</li>

<li>dyadic function [<a href="chapter1.html#functions">1</a>]</li>

<li>each (<code>¨</code>) [<a href="chapter3.html#each">1</a>]

<ul>

<li>as iterative process [<a href="chapter7.html#section-7.6-control-of-execution-iteration">1</a>]</li>

</ul></li>

<li>editing

<ul>

<li>del to initiate [<a href="chapter3.html#defined-function-structure">1</a>]</li>

<li>del to leave [<a href="chapter3.html#defined-function-structure">1</a>]</li>

<li>selection of editor [<a href="appendixB.html#selecting-an-editor">1</a>]</li>

<li>with full-screen editor [<a href="appendixB.html#the-apl2-full-screen-editor-editor-2">1</a>]</li>

<li>with line editor [<a href="appendixB.html#the-apl2-line-editor-editor-1">1</a>]</li>

</ul></li>

<li><code>)EDITOR</code> [<a href="appendixB.html#selecting-an-editor">1</a>]</li>

<li>empty vector

<ul>

<li>branch to [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>character [<a href="chapter2.html#creating-an-empty-vector">1</a>]</li>

<li>creating with reshape [<a href="chapter5.html#reshape">1</a>]</li>

<li>defined [<a href="chapter2.html#section-2.3-empty-vectors">1</a>]</li>

<li>how created [<a href="chapter2.html#creating-an-empty-vector">1</a>]</li>

<li>numeric [<a href="chapter2.html#creating-an-empty-vector">1</a>]</li>

<li>reduction of [<a href="chapter3.html#using-derived-functions">1</a>]</li>

</ul></li>

<li>enclose (<code>⊂</code>) [<a href="chapter5.html#nested-reshaping-of-an-array-enclose">1</a>]

<ul>

<li>relationship to disclose (<code>⊃</code>) [<a href="chapter5.html#nested-reshaping-of-an-array-disclose">1</a>]</li>

</ul></li>

<li>enclose with axis (<code>⊂[]</code>) [<a href="chapter5.html#enclose-with-axis">1</a>]</li>

<li>encode (<code>⊤</code>) [<a href="chapter6.html#encode">1</a>]</li>

<li>endless loop [<a href="chapter7.html#stopping-your-program">1</a>]</li>

<li>enlist (<code>∊</code>) [<a href="chapter5.html#enlist">1</a>]

<ul>

<li>relationship to ravel (<code>,</code>) [<a href="chapter5.html#enlist">1</a>]</li>

</ul></li>

<li>E notation [<a href="chapter1.html#numbers">1</a>, <a href="chapter7.html#format-by-specification">2</a>]</li>

<li>enter key

<ul>

<li>to signal end of input [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

</ul></li>

<li>environment [<a href="chapter4.html">1</a>]</li>

<li>equal (<code>=</code>) [<a href="chapter6.html#relational-functions">1</a>]</li>

<li><code>)ERASE</code> [<a href="chapter4.html#removing-objects-from-the-active-workspace-erase">1</a>]</li>

<li>error checking [<a href="chapter3.html#errors-during-program-execution">1</a>]</li>

<li>error reports

<ul>

<li><code>DOMAIN ERROR</code> [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li><code>INDEX ERROR</code> [<a href="chapter6.html#indexing">1</a>]</li>

<li><code>LENGTH ERROR</code> [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li>purpose of caret (<code>^</code>) [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li><code>SYNTAX ERROR</code> [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li>types of [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li><code>VALUE ERROR</code> [<a href="chapter1.html#types-of-errors">1</a>]</li>

</ul></li>

<li>errors

<ul>

<li>clearing with <code>→</code> [<a href="chapter1.html#clearing-errors">1</a>]</li>

<li>clearing with <code>)RESET</code> [<a href="chapter1.html#clearing-errors">1</a>]</li>

<li>during function execution [<a href="chapter3.html#errors-during-program-execution">1</a>]</li>

<li>types of [<a href="chapter1.html#types-of-errors">1</a>]</li>

</ul></li>

<li>error trapping [<a href="postscript.html#event-handling">1</a>]</li>

<li>escape branch (<code>→</code>) [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>evaluated input (<code>⎕</code>) [<a href="chapter7.html#evaluated-input">1</a>]</li>

<li>evaluation

<ul>

<li>how different from arithmetic [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

<li>of expressions [<a href="chapter1.html#section-1.4-evaluation-of-expressions">1</a>]</li>

<li>of expression with parentheses [<a href="chapter1.html#use-of-parentheses">1</a>]</li>

<li>order of [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

<li>right-to-left rule [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

</ul></li>

<li>event handling [<a href="postscript.html#event-handling">1</a>]</li>

<li>exclusive or (<code>≠</code>) [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>execute (<code>⍎</code>) [<a href="chapter7.html#executing-character-input">1</a>]</li>

<li>execution

<ul>

<li>default order of [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

<li>interrupting [<a href="chapter7.html#interrupt">1</a>]</li>

<li>of an expression [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

<li>of expression with parentheses [<a href="chapter1.html#use-of-parentheses">1</a>]</li>

<li>restarting [<a href="chapter7.html#restarting-your-program">1</a>]</li>

<li>termination of [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

</ul></li>

<ul>

<li>with <code>)CONTINUE</code> [<a href="chapter1.html#section-1.5-saving-your-work">1</a>]</li>

</ul></li>

<li>expand (<code>\</code>) [<a href="chapter6.html#selecting-items-with-a-mask-expansion">1</a>]</li>

<li>expand (<code>⍀</code>) [<a href="chapter6.html#selecting-items-with-a-mask-expansion">1</a>]</li>

<li>explicit result

<ul>

<li>of a defined function [<a href="chapter3.html#defined-function-structure">1</a>]</li>

<li>of a function [<a href="chapter1.html#functions">1</a>]</li>

</ul></li>

<li>exponential (<code>⋆</code>) [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>exponential notation [<a href="chapter7.html#format-by-specification">1</a>]</li>

<li>expressions

<ul>

<li>as items of a vector [<a href="chapter1.html#vector-notation">1</a>]</li>

<li>evaluation of [<a href="chapter1.html#section-1.4-evaluation-of-expressions">1</a>]</li>

<li>several functions in one [<a href="chapter1.html#section-1.4-evaluation-of-expressions">1</a>]</li>

</ul></li>

<li>external names [<a href="postscript.html#external-names-and-associated-processors">1</a>]</li>

<li>factorial (<code>!</code>) [<a href="chapter6.html#factorial-and-binomial">1</a>]</li>

<li>Fibonacci numbers [<a href="chapter7.html#fibonacci-numbers">1</a>]</li>

<li>first (<code>↑</code>) [<a href="chapter2.html#selecting-items-from-a-vector-first">1</a>, <a href="chapter5.html#first">2</a>]

<ul>

<li>compared to take (1<code>↑</code>) [<a href="chapter2.html#selecting-items-from-a-vector-take">1</a>]</li>

<li>of an empty [<a href="chapter2.html#selecting-items-from-a-vector-first">1</a>]</li>

<li>on empty [<a href="chapter5.html#first">1</a>]</li>

<li>relationship to pick (<code>⊃</code>) [<a href="chapter2.html#selecting-items-from-a-vector-first">1</a>]</li>

</ul></li>

<li>floor (<code>⌊</code>) [<a href="chapter2.html#scalar-functions-floor-and-ceiling">1</a>]</li>

<li>format by specification [<a href="chapter7.html#format-by-specification">1</a>]</li>

<li>format (<code>⍕</code>)

<ul>

<li>by example [<a href="chapter7.html#format-by-example">1</a>]</li>

<li>by specification [<a href="chapter7.html#format">1</a>]</li>

</ul></li>

<li>formula, closed [<a href="chapter7.html#closed-formula">1</a>]</li>

<li>function [<a href="chapter1.html#simple-arithmetic">1</a>]

<ul>

<li>applied to character data [<a href="chapter2.html#functions-that-work-on-characters">1</a>]</li>

<li>Boolean [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>compared to operator [<a href="chapter3.html#section-3.1-operators-apply-to-functions">1</a>]</li>

<li>comparison of dyadic and monadic [<a href="chapter1.html#functions">1</a>]</li>

<li>defined [<a href="chapter1.html#functions">1</a>, <a href="chapter3.html#section-3.2-programs-remember-expressions">2</a>]</li>

<li>defined operator [<a href="chapter3.html#section-3.2-programs-remember-expressions">1</a>]</li>

<li>derived [<a href="chapter1.html#operators">1</a>, <a href="chapter3.html#section-3.1-operators-apply-to-functions">2</a>]</li>

<li>dyadic [<a href="chapter1.html#functions">1</a>]</li>

<li>dyadic used with reduction [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>inverse [<a href="chapter6.html#matrix-inverse">1</a>]</li>

<li>monadic [<a href="chapter1.html#functions">1</a>]</li>

<li>name of derived [<a href="chapter3.html#naming-derived-functions">1</a>]</li>

<li>primitive [<a href="chapter1.html#functions">1</a>]</li>

<li>relational [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>scalar [<a href="chapter2.html#section-2.5-scalar-functions">1</a>, <a href="chapter5.html#scalar-functions">2</a>]</li>

<li>several in an expression [<a href="chapter1.html#section-1.4-evaluation-of-expressions">1</a>]</li>

</ul></li>

<li>functions

<ul>

<li>system [<a href="postscript.html#system-functions-and-system-variables">1</a>]</li>

</ul></li>

<li>global names [<a href="chapter3.html#local-names">1</a>]

<ul>

<li>shadowed by local names [<a href="chapter3.html#local-names">1</a>]</li>

</ul></li>

<li>grade down (<code>⍒</code>) [<a href="chapter6.html#grade-up-and-grade-down">1</a>]</li>

<li>grade up (<code>⍋</code>) [<a href="chapter6.html#grade-up-and-grade-down">1</a>]</li>

<li>graphs [<a href="chapter6.html#indexing">1</a>]</li>

<li>greater than (<code>></code>) [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>greater than or equal (<code>≥</code>) [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>groups

<ul>

<li>copying [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]</li>

</ul></li>

<li>header

<ul>

<li>of a defined function [<a href="chapter3.html#defined-function-structure">1</a>]</li>

<li>of a defined operator [<a href="chapter3.html#defined-operator-structure">1</a>]</li>

<li>of a defined sequence [<a href="chapter3.html#defined-sequence-structure">1</a>]</li>

<li>of a program [<a href="chapter3.html#program-structure">1</a>]</li>

<li>parts of [<a href="chapter3.html#program-structure">1</a>]</li>

<li>to access <span class="small-caps">APL</span> editor [<a href="appendixB.html#the-apl2-full-screen-editor-editor-2">1</a>]</li>

</ul></li>

<li>header syntax [<a href="chapter3.html#header-syntax">1</a>]</li>

<li>histogram [<a href="chapter6.html#indexing">1</a>]</li>

<li>hyperbolic arc cosine [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>hyperbolic arc sine [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>hyperbolic arc tangent [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>hyperbolic cosine [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>hyperbolic functions [<a href="chapter6.html#trigonometric-functions">1</a>]</li>

<li>hyperbolic sine [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>hyperbolic tangent [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>hyperplanes [<a href="chapter5.html#reshape">1</a>]</li>

<li>identity element

<ul>

<li>using reduction to determine [<a href="chapter3.html#using-derived-functions">1</a>]</li>

</ul></li>

<li>identity matrix [<a href="chapter6.html#matrix-inverse">1</a>]</li>

<li>imaginary part of a complex number [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>immediate execution mode [<a href="chapter3.html#defining-a-program">1</a>, <a href="chapter4.html#seeing-the-state-indicator-sis">2</a>, <a href="chapter7.html#evaluated-input">3</a>]</li>

<li>implication [<a href="chapter6.html#section-6.2-selecting-subsets-of-arrays">1</a>]</li>

<li>indexed assignment [<a href="chapter6.html#section-6.2-selecting-subsets-of-arrays">1</a>, <a href="chapter6.html#selective-assignment">2</a>]</li>

<li>indexed specification [<a href="chapter6.html#section-6.2-selecting-subsets-of-arrays">1</a>, <a href="chapter6.html#selective-assignment">2</a>]</li>

<li><code>INDEX ERROR</code> [<a href="chapter6.html#indexing">1</a>]</li>

<li>indexing</li>

<li>scatter [<a href="appendixF.html#indexing">1</a>]</li>

<li>indexing (<code>[]</code>) [<a href="chapter6.html#indexing">1</a>]

<ul>

<li>inverse of index of [<a href="chapter6.html#membership">1</a>]</li>

<li>of arrays [<a href="chapter6.html#indexing">1</a>]</li>

<li>of vectors [<a href="chapter2.html#selecting-items-from-a-vector-indexing">1</a>]</li>

<li>shape of [<a href="chapter6.html#indexing">1</a>]</li>

<li>values selected by [<a href="chapter6.html#indexing">1</a>]</li>

</ul></li>

<li>indexing (<code>⌷</code>) [<a href="appendixF.html#indexing">1</a>]</li>

<li>index of (<code>⍳</code>) [<a href="chapter6.html#index-of">1</a>]</li>

<li>infinite loop [<a href="chapter7.html#stopping-your-program">1</a>, <a href="chapter7.html#infinite-loops">2</a>, <a href="chapter7.html#inadvertent-recursion">3</a>]</li>

<li>infinite recursion [<a href="chapter7.html#inadvertent-recursion">1</a>]</li>

<li>inner product (<code>.</code>) [<a href="chapter5.html#inner-product">1</a>, <a href="chapter6.html#decode">2</a>]</li>

<li>input [<a href="chapter7.html#section-7.3-prompting-for-input">1</a>]

<ul>

<li>after output [<a href="chapter7.html#character-input-following-character-output">1</a>]</li>

<li><span class="small-caps">APL</span> prompt for [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

<li>character (<code>⍞</code>) [<a href="chapter7.html#character-input">1</a>]</li>

<li>evaluated (<code>⎕</code>) [<a href="chapter7.html#evaluated-input">1</a>]</li>

<li>quad-prime (<code>⍞</code>) [<a href="chapter7.html#character-input">1</a>]</li>

</ul></li>

<li>integers

<ul>

<li>identify public libraries [<a href="chapter4.html#public-libraries">1</a>]</li>

<li>producing consecutive [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

<li>producing even [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

<li>representation of [<a href="chapter1.html#numbers">1</a>]</li>

<li>round to the nearest [<a href="chapter2.html#scalar-functions-floor-and-ceiling">1</a>]</li>

</ul></li>

<li>interrupt [<a href="chapter7.html#interrupt">1</a>]</li>

<li>interruption execution [<a href="chapter7.html#interrupt">1</a>]</li>

<li>intersection of two arrays [<a href="chapter6.html#without">1</a>]</li>

<li>interval (<code>⍳</code>) [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

<li>interval-each (<code>⍳¨</code>) [<a href="chapter3.html#each">1</a>]</li>

<li>inverse [<a href="chapter6.html#matrix-inverse">1</a>]</li>

<li>inverse of a matrix [<a href="chapter6.html#matrix-inverse">1</a>]</li>

<li>items [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]

<ul>

<li>in a vector [<a href="chapter1.html#vector-notation">1</a>]</li>

</ul></li>

<li>iteration

<ul>

<li>defined [<a href="chapter7.html#section-7.6-control-of-execution-iteration">1</a>]</li>

<li>not always needed in <span class="small-caps">APL</span> [<a href="chapter1.html#section-1.2-arithmetic-on-arrays">1</a>]</li>

</ul></li>

<li>keyboard [<a href="chapter1.html">1</a>, <a href="appendixE.html">2</a>]</li>

<li>labels [<a href="chapter3.html#local-names">1</a>, <a href="chapter7.html#labels">2</a>]</li>

<li>laminate (<code>,[]</code>) [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>least squares fit [<a href="chapter6.html#matrix-inverse">1</a>, <a href="chapter6.html#matrix-divide">2</a>]</li>

<li>length

<ul>

<li>of an empty vector [<a href="chapter2.html#creating-an-empty-vector">1</a>]</li>

<li>of a vector [<a href="chapter2.html#measuring-the-size-of-a-vector-shape">1</a>]</li>

</ul></li>

<li><code>LENGTH ERROR</code> [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li>less than or equal (<code>≤</code>) [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>letters

<ul>

<li>used in names [<a href="chapter1.html#names">1</a>]</li>

</ul></li>

<li>libraries

<ul>

<li>adding workspaces to [<a href="chapter4.html#establishing-a-workspace-from-your-work">1</a>]</li>

<li>numbers of [<a href="chapter4.html#public-libraries">1</a>]</li>

<li>private [<a href="chapter4.html#section-4.1-libraries">1</a>]</li>

<li>public [<a href="chapter4.html#public-libraries">1</a>]</li>

<li>removing workspaces from [<a href="chapter4.html#removing-a-workspace-from-the-library-drop">1</a>]</li>

<li>retrieving a workspace from [<a href="chapter4.html#loading-a-workspace-from-the-library-load">1</a>]</li>

</ul></li>

<li>library workspace [<a href="chapter4.html#section-4.1-libraries">1</a>]</li>

<li>line zero alternative name for header of a program [<a href="chapter3.html#program-structure">1</a>]</li>

<li>local names [<a href="chapter3.html#local-names">1</a>, <a href="chapter3.html#using-local-names">2</a>]

<ul>

<li>shadowing global names [<a href="chapter3.html#local-names">1</a>]</li>

</ul></li>

<li>logarithm (<code>⍟</code>) [<a href="chapter6.html#logarithm">1</a>]

<ul>

<li>common [<a href="chapter6.html#logarithm">1</a>]</li>

<li>natural [<a href="chapter6.html#logarithm">1</a>]</li>

</ul></li>

<li>loop [<a href="chapter7.html#good-programming-practices-with-branching">1</a>]

<ul>

<li>implicit [<a href="chapter7.html#good-programming-practices-with-branching">1</a>]</li>

<li>infinite [<a href="chapter7.html#stopping-your-program">1</a>, <a href="chapter7.html#infinite-loops">2</a>]</li>

<li>termination of [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>tracing [<a href="chapter7.html#tracing-execution">1</a>]</li>

</ul></li>

<li>magnitude (<code>∣</code>) [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>]

<ul>

<li>relationship to direction (<code>×</code>) [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>]</li>

</ul></li>

<li>match (<code>≡</code>) [<a href="chapter6.html#match">1</a>]</li>

<li>matrix [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]

<ul>

<li>adding a column to [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>adding a row to [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>from vectors using catenate with fractional axis [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>from vectors using laminate [<a href="chapter5.html#catenate-with-axis">1</a>]</li>

<li>name of rank-2 array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>reshape to create [<a href="chapter5.html#reshape">1</a>]</li>

<li>turning a vector into a one column matrix [<a href="chapter5.html#ravel-with-axis">1</a>]</li>

</ul></li>

<li>matrix inverse [<a href="chapter6.html#matrix-inverse">1</a>]</li>

<li>matrix product [<a href="chapter5.html#inner-product">1</a>, <a href="chapter6.html#matrix-inverse">2</a>]</li>

<li>maximum (<code>⌈</code>) [<a href="chapter2.html#scalar-functions-maximum-and-minimum">1</a>]</li>

<li>maximum-reduction (<code>⌈/</code>) [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>membership (<code>∊</code>) [<a href="chapter6.html#membership">1</a>]</li>

<li>minimum (<code>⌊</code>) [<a href="chapter2.html#scalar-functions-maximum-and-minimum">1</a>]</li>

<li>minimum-reduction (<code>⌊/</code>) [<a href="chapter3.html#reduction-on-vectors">1</a>]

<ul>

<li>of empty vector [<a href="chapter3.html#using-derived-functions">1</a>]</li>

</ul></li>

<li>minus sign [<a href="chapter1.html#numbers">1</a>]</li>

<li>modulus [<a href="chapter2.html#scalar-functions-residue-and-reciprocal">1</a>]</li>

<li>monadic function [<a href="chapter1.html#functions">1</a>]</li>

<li>monadic operator [<a href="chapter3.html#using-derived-functions">1</a>]</li>

<li>moving-window reduction [<a href="chapter5.html#n-wise-reduction">1</a>]</li>

<li>multiplication (<code>×</code>) [<a href="chapter1.html#simple-arithmetic">1</a>]

<ul>

<li>alternate symbols not allowed [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

<li>relationship to logarithm [<a href="chapter6.html#logarithm">1</a>]</li>

<li>relationship to power [<a href="chapter2.html#scalar-function-power">1</a>, <a href="chapter6.html#power-and-exponential">2</a>]</li>

</ul></li>

<li>multiplication-reduction of empty vector [<a href="chapter3.html#using-derived-functions">1</a>]</li>

<li>names

<ul>

<li>assignment of [<a href="chapter1.html#assignment">1</a>]</li>

<li>changing the name of the active workspace [<a href="chapter4.html#name-of-the-active-workspace">1</a>]</li>

<li>external [<a href="postscript.html#external-names-and-associated-processors">1</a>]</li>

<li>global [<a href="chapter3.html#local-names">1</a>, <a href="chapter3.html#using-local-names">2</a>]</li>

<li>local [<a href="chapter3.html#local-names">1</a>, <a href="chapter3.html#using-local-names">2</a>]</li>

<li>local to a program [<a href="chapter3.html#local-names">1</a>]</li>

<li>of active workspace [<a href="chapter4.html#name-of-the-active-workspace">1</a>]</li>

<li>rules for constructing [<a href="chapter1.html#names">1</a>]</li>

<li>shadowed [<a href="chapter3.html#local-names">1</a>]</li>

<li>shared [<a href="postscript.html#shared-variables">1</a>]</li>

<li>variables for data [<a href="chapter1.html#assignment">1</a>]</li>

</ul></li>

<li>Napier

<ul>

<li>and logarithms [<a href="chapter6.html#logarithm">1</a>]</li>

</ul></li>

<li>natural logarithm (<code>⍟</code>) [<a href="chapter6.html#logarithm">1</a>]</li>

<li>negation (<code>−</code>) [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

<li>negative number [<a href="chapter1.html#numbers">1</a>]</li>

<li>negative sign (<code>¯</code>) [<a href="chapter1.html#numbers">1</a>]

<ul>

<li>differs from minus sign (<code>−</code>) [<a href="chapter1.html#numbers">1</a>]</li>

</ul></li>

<li>nested array [<a href="chapter1.html#terms-for-data">1</a>, <a href="chapter2.html#scalar-functions-and-nested-arrays">2</a>, <a href="chapter5.html#section-5.1-properties-of-arrays">3</a>]</li>

<li>nested scalar

<ul>

<li>created by reduction [<a href="chapter3.html#using-derived-functions">1</a>]</li>

<li>created with enclose [<a href="chapter5.html#nested-reshaping-of-an-array-enclose">1</a>]</li>

</ul></li>

<li>nested vector [<a href="chapter1.html#terms-for-data">1</a>]</li>

<li>nested versus simple array [<a href="chapter1.html#terms-for-data">1</a>]</li>

<li>niladic branch (<code>→</code>) [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>niladic function [<a href="chapter3.html#section-3.2-programs-remember-expressions">1</a>]</li>

<li>not equal (<code>≠</code>) [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>numbers

<ul>

<li>complex [<a href="chapter6.html#power-and-exponential">1</a>, <a href="postscript.html#complex-numbers">2</a>]</li>

<li>consecutive [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

<li>conventions not recognized in <span class="small-caps">APL</span> [<a href="chapter1.html#numbers">1</a>]</li>

<li>counting digits in [<a href="chapter6.html#logarithm">1</a>]</li>

<li>determine number of digits in [<a href="chapter6.html#logarithm">1</a>]</li>

<li>display of [<a href="chapter1.html#numbers">1</a>]</li>

<li>entering [<a href="chapter1.html#numbers">1</a>]</li>

<li>Fibonacci [<a href="chapter7.html#fibonacci-numbers">1</a>]</li>

<li>formatting [<a href="chapter7.html#section-7.5-controlling-output">1</a>]</li>

<li>fractional [<a href="chapter1.html#numbers">1</a>]</li>

<li>from character data [<a href="chapter6.html#index-of">1</a>]</li>

<li>generating random [<a href="chapter6.html#section-6.5-generating-random-numbers">1</a>]</li>

<li>mixed base [<a href="chapter6.html#decode">1</a>]</li>

<li>negative [<a href="chapter1.html#numbers">1</a>]</li>

<li>random [<a href="chapter6.html#section-6.5-generating-random-numbers">1</a>]</li>

<li>representation of [<a href="chapter1.html#numbers">1</a>]</li>

<li>roots of [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>rounding [<a href="chapter1.html#numbers">1</a>, <a href="chapter2.html#scalar-functions-floor-and-ceiling">2</a>]</li>

<li>used in names [<a href="chapter1.html#names">1</a>]</li>

<li>very large or very small [<a href="chapter1.html#numbers">1</a>]</li>

</ul></li>

<li>number sequence

<ul>

<li>decreasing [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

<li>increasing [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

</ul></li>

<li>numeric data

<ul>

<li>from character data [<a href="chapter7.html#executing-character-input">1</a>]</li>

<li>in a vector with character data [<a href="chapter2.html#vectors-with-both-numbers-and-characters">1</a>]</li>

</ul></li>

<li>n-wise reduction (<code>/</code>) [<a href="chapter5.html#n-wise-reduction">1</a>]</li>

<li>one

<ul>

<li>as truth value [<a href="chapter6.html#section-6.1-ways-of-comparing">1</a>]</li>

</ul></li>

<li>operands of an operator [<a href="chapter1.html#operators">1</a>, <a href="chapter3.html#using-derived-functions">2</a>]</li>

<li>operation [<a href="chapter1.html#terms-for-operations">1</a>]</li>

<li>operator [<a href="chapter1.html#adding-up-numbers">1</a>]

<ul>

<li>compared to function [<a href="chapter3.html#section-3.1-operators-apply-to-functions">1</a>]</li>

<li>defined [<a href="chapter1.html#operators">1</a>, <a href="chapter3.html#section-3.2-programs-remember-expressions">2</a>]</li>

<li>deriving functions [<a href="chapter1.html#operators">1</a>]</li>

<li>dyadic [<a href="chapter3.html#header-syntax">1</a>]</li>

<li>inner product [<a href="chapter5.html#inner-product">1</a>]</li>

<li>monadic [<a href="chapter3.html#using-derived-functions">1</a>, <a href="chapter3.html#header-syntax">2</a>]</li>

<li>n-wise reduction [<a href="chapter5.html#n-wise-reduction">1</a>]</li>

<li>outer product [<a href="chapter5.html#outer-product">1</a>]</li>

<li>primitive [<a href="chapter1.html#operators">1</a>]</li>

<li>reduction [<a href="chapter1.html#adding-up-numbers">1</a>]</li>

</ul></li>

<li>outer product (<code>∘.</code>) [<a href="chapter5.html#outer-product">1</a>]</li>

<li>output [<a href="chapter5.html#default-display-of-arrays">1</a>, <a href="chapter7.html#section-7.4-output-with-quad-and-quote-quad">2</a>]

<ul>

<li>before input [<a href="chapter7.html#character-input-following-character-output">1</a>]</li>

<li>quad-prime [<a href="chapter7.html#section-7.4-output-with-quad-and-quote-quad">1</a>]</li>

</ul></li>

<li>parentheses

<ul>

<li>evaluating an expression with [<a href="chapter1.html#use-of-parentheses">1</a>]</li>

<li>in assignment [<a href="chapter6.html#selective-assignment">1</a>]</li>

<li>in header [<a href="chapter3.html#defined-operator-structure">1</a>]</li>

<li>redundant [<a href="chapter1.html#use-of-parentheses">1</a>, <a href="chapter1.html#vector-notation">2</a>]</li>

<li>to group items in a vector [<a href="chapter1.html#vector-notation">1</a>]</li>

</ul></li>

<li>parity check

<ul>

<li>expression for [<a href="chapter6.html#boolean-functions">1</a>]</li>

</ul></li>

<li>partition (<code>⊂</code>) [<a href="appendixF.html#partition">1</a>]</li>

<li><code>)PCOPY</code> [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]</li>

<li>period (<code>.</code>)

<ul>

<li>not used to separate groups of digits [<a href="chapter1.html#numbers">1</a>]</li>

</ul></li>

<li>phase of a complex number [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>pick (<code>⊃</code>) [<a href="chapter2.html#selecting-items-from-a-vector-pick">1</a>, <a href="chapter5.html#pick">2</a>]

<ul>

<li>on a matrix [<a href="chapter5.html#pick">1</a>]</li>

<li>relationship to first (<code>↑</code>) [<a href="chapter2.html#selecting-items-from-a-vector-first">1</a>]</li>

<li>relationship to indexing [<a href="chapter2.html#selecting-items-from-a-vector-indexing">1</a>]</li>

</ul></li>

<li>pi-times [<a href="chapter6.html#pi-times">1</a>]</li>

<li>plus-reduction (<code>+/</code>) [<a href="chapter1.html#adding-up-numbers">1</a>]

<ul>

<li>of empty vector [<a href="chapter3.html#using-derived-functions">1</a>]</li>

<li>to add up the first 100 integers [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>]</li>

</ul></li>

<li>power (<code>⋆</code>) [<a href="chapter2.html#scalar-function-power">1</a>, <a href="chapter6.html#power-and-exponential">2</a>]

<ul>

<li>to find square root [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>with negative exponents [<a href="chapter6.html#power-and-exponential">1</a>]</li>

</ul></li>

<li>primitive functions [<a href="chapter1.html#functions">1</a>]</li>

<li>primitive operator [<a href="chapter1.html#operators">1</a>]</li>

<li>private libraries [<a href="chapter4.html#section-4.1-libraries">1</a>]</li>

<li>processors

<ul>

<li>associated [<a href="postscript.html#external-names-and-associated-processors">1</a>]</li>

</ul></li>

<li>programming

<ul>

<li>bottom-up [<a href="chapter8.html#building-and-maintaining-the-magazine-matrix">1</a>]</li>

<li>prompting for input [<a href="chapter7.html#section-7.3-prompting-for-input">1</a>]</li>

<li>structured [<a href="chapter7.html#section-7.6-control-of-execution-iteration">1</a>]</li>

</ul></li>

<li>programs

<ul>

<li>branch control in [<a href="chapter7.html#section-7.1-control-of-execution-branching">1</a>]</li>

<li>debugging [<a href="chapter7.html#section-7.2-debugging-your-program">1</a>]</li>

<li>header [<a href="chapter3.html#program-structure">1</a>]</li>

<li>labels [<a href="chapter7.html#labels">1</a>]</li>

<li>looping [<a href="chapter7.html#more-about-unconditional-branching">1</a>]</li>

<li>restarting [<a href="chapter7.html#restarting-your-program">1</a>]</li>

<li>stopping [<a href="chapter7.html#stopping-where-you-choose">1</a>]</li>

<li>structure of [<a href="chapter3.html#program-structure">1</a>]</li>

<li>tracing [<a href="chapter7.html#tracing-execution">1</a>]</li>

<li>types of [<a href="chapter3.html#defined-sequence-structure">1</a>]</li>

</ul></li>

<li>prompting for input [<a href="chapter7.html#section-7.3-prompting-for-input">1</a>]</li>

<li>protected copy [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]</li>

<li>prototype [<a href="chapter5.html#first">1</a>]</li>

<li>pythagoriean functions [<a href="chapter6.html#trigonometric-functions">1</a>]</li>

<li>quad input (<code>⎕</code>) [<a href="chapter7.html#evaluated-input">1</a>]</li>

<li>quad output (<code>⎕</code>) [<a href="chapter7.html#section-7.4-output-with-quad-and-quote-quad">1</a>]</li>

<li>quad-prime input after output</li>

<li>quad-prime input (<code>⍞</code>) [<a href="chapter7.html#character-input">1</a>]</li>

<li>quad-prime output (<code>⍞</code>) [<a href="chapter7.html#quote-quad-for-output">1</a>]</li>

<li>quad-quote output (<code>⍞</code>) [<a href="chapter7.html#section-7.4-output-with-quad-and-quote-quad">1</a>]</li>

<ul>

<li>with <code>)CONTINUE</code> [<a href="chapter1.html#section-1.5-saving-your-work">1</a>]</li>

</ul></li>

<li>quotation mark (<code>⊤</code>)

<ul>

<li>as a character [<a href="chapter2.html#character-vectors">1</a>]</li>

<li>to delimit character data [<a href="chapter2.html#section-2.2-character-data">1</a>]</li>

</ul></li>

<li>quote-quad input after output</li>

<li>quote-quad output (<code>⍞</code>) [<a href="chapter7.html#section-7.4-output-with-quad-and-quote-quad">1</a>, <a href="chapter7.html#quote-quad-for-output">2</a>]</li>

<li>random numbers [<a href="chapter6.html#section-6.5-generating-random-numbers">1</a>]</li>

<li>ravel (<code>,</code>) [<a href="chapter5.html#ravel">1</a>]

<ul>

<li>relationship to enlist (<code>∊</code>) [<a href="chapter5.html#enlist">1</a>]</li>

<li>relationship to reshape (<code>⍴</code>) [<a href="chapter5.html#ravel">1</a>]</li>

</ul></li>

<li>ravel with axis (<code>,[]</code>) [<a href="chapter5.html#ravel-with-axis">1</a>]</li>

<li>real numbers [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>real part of a complex number [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>reciprocal (<code>÷</code>) [<a href="chapter2.html#scalar-functions-residue-and-reciprocal">1</a>]</li>

<li>recursion [<a href="chapter7.html#section-7.7-control-of-execution-recursion">1</a>, <a href="chapter7.html#inadvertent-recursion">2</a>]</li>

<li>recursive function [<a href="chapter7.html#section-7.7-control-of-execution-recursion">1</a>]</li>

<li>reduction

<ul>

<li>with inner product [<a href="chapter5.html#inner-product">1</a>]</li>

</ul></li>

<li>reduction (<code>/</code>)

<ul>

<li>as iterative process [<a href="chapter7.html#section-7.6-control-of-execution-iteration">1</a>]</li>

<li>domain of [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>of an empty vector [<a href="chapter3.html#using-derived-functions">1</a>]</li>

<li>on vectors [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>to add a set of numbers [<a href="chapter1.html#adding-up-numbers">1</a>]</li>

<li>to find the largest or smallest in [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>with Boolean functions [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>with catenate [<a href="chapter3.html#using-derived-functions">1</a>]</li>

<li>with nested arguments [<a href="chapter3.html#using-derived-functions">1</a>]</li>

</ul></li>

<li>reduction with axis (<code>/[]</code>) [<a href="chapter5.html#reduction-with-axis">1</a>]</li>

<li>relational functions [<a href="chapter6.html#relational-functions">1</a>]

<ul>

<li>effect of machine arithmetic [<a href="chapter6.html#relational-functions">1</a>]</li>

</ul></li>

<li>relational structures [<a href="chapter8.html#designing-the-application">1</a>]</li>

<li>remainder [<a href="chapter2.html#scalar-functions-residue-and-reciprocal">1</a>]</li>

<li>replacement of values [<a href="chapter6.html#selective-assignment">1</a>]</li>

<li>replicate (<code>/</code>) [<a href="chapter6.html#selecting-items-with-a-mask-replication">1</a>]</li>

<li>replicate with axis (<code>/[]</code>) [<a href="chapter6.html#selecting-items-with-a-mask-replication">1</a>]</li>

<li><code>)RESET</code> [<a href="chapter1.html#clearing-errors">1</a>]</li>

<li>reshape (<code>⍴</code>) [<a href="chapter5.html#reshape">1</a>]

<ul>

<li>relationship to ravel (<code>,</code>) [<a href="chapter5.html#ravel">1</a>]</li>

<li>relationship to shape (<code>⍴</code>) [<a href="chapter5.html#shape">1</a>]</li>

</ul></li>

<li>residue (<code>∣</code>) [<a href="chapter2.html#scalar-functions-residue-and-reciprocal">1</a>]</li>

<li>restarting your program [<a href="chapter7.html#restarting-your-program">1</a>]</li>

<li>result

<ul>

<li>displayed at left margin of the next line. [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

</ul></li>

<li>result, explicit

<ul>

<li>of a function [<a href="chapter1.html#functions">1</a>]</li>

</ul></li>

<li>resuming execution [<a href="chapter7.html#restarting-your-program">1</a>]</li>

<li>return key

<ul>

<li>to signal end of input [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

</ul></li>

<li>reverse (<code>⌽</code>) [<a href="chapter6.html#reverse">1</a>]</li>

<li>reverse with axis (<code>⌽[]</code>) [<a href="chapter6.html#reverse">1</a>]</li>

<li>reversing a selection with not [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>right arrow (<code>→</code>)

<ul>

<li>to clear error [<a href="chapter1.html#clearing-errors">1</a>]</li>

<li>to clear state indicator [<a href="chapter4.html#seeing-the-state-indicator-sis">1</a>]</li>

<li>to terminate program execution [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

</ul></li>

<li>right-to-left rule [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

<li>roots [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>rotate (<code>⌽</code>) [<a href="chapter6.html#rotate">1</a>]</li>

<li>rotate with axis (<code>⌽[]</code>) [<a href="chapter6.html#rotate">1</a>]</li>

<li>rounding [<a href="chapter1.html#numbers">1</a>, <a href="chapter2.html#scalar-functions-floor-and-ceiling">2</a>, <a href="chapter7.html#format-by-specification">3</a>]</li>

<li>row-major order [<a href="chapter5.html#reshape">1</a>, <a href="chapter5.html#enlist">2</a>]</li>

<li>rows of an array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>rules

<ul>

<li>for evaluation of expressions [<a href="chapter1.html#order-of-evaluation">1</a>]</li>

<li>for names [<a href="chapter1.html#names">1</a>]</li>

</ul></li>

<ul>

<li>See stop facility</li>

</ul></li>

<li>saving workspace

<ul>

<li>with <code>)CONTINUE</code> [<a href="chapter1.html#section-1.5-saving-your-work">1</a>, <a href="chapter4.html">2</a>]</li>

</ul></li>

<li>scalar [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]

<ul>

<li>created with enclose [<a href="chapter5.html#nested-reshaping-of-an-array-enclose">1</a>]</li>

<li>from a vector [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>name of rank-0 array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>nested [<a href="chapter3.html#using-derived-functions">1</a>, <a href="chapter5.html#nested-reshaping-of-an-array-enclose">2</a>]</li>

<li>produced by reduction [<a href="chapter3.html#using-derived-functions">1</a>]</li>

<li>simple [<a href="chapter1.html#terms-for-data">1</a>, <a href="chapter5.html#section-5.1-properties-of-arrays">2</a>]</li>

</ul></li>

<li>scalar extension [<a href="chapter2.html#scalar-conformability-and-scalar-extension">1</a>, <a href="chapter5.html#scalar-functions">2</a>]</li>

<li>scalar functions [<a href="chapter2.html#section-2.5-scalar-functions">1</a>, <a href="chapter5.html#scalar-functions">2</a>]

<ul>

<li>Boolean [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>conformability of arguments with [<a href="chapter2.html#scalar-conformability-and-scalar-extension">1</a>]</li>

<li>each has no effect on [<a href="chapter3.html#each">1</a>]</li>

<li>extension for conformability [<a href="chapter2.html#scalar-conformability-and-scalar-extension">1</a>]</li>

<li>maximum (<code>⌈</code>) [<a href="chapter2.html#scalar-functions-maximum-and-minimum">1</a>]</li>

<li>minimum (<code>⌊</code>) [<a href="chapter2.html#scalar-functions-maximum-and-minimum">1</a>]</li>

<li>power (<code>⋆</code>) [<a href="chapter2.html#scalar-function-power">1</a>]</li>

<li>properties of [<a href="chapter2.html#section-2.5-scalar-functions">1</a>]</li>

<li>relational [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>with nested arguments [<a href="chapter5.html#scalar-functions">1</a>]</li>

</ul></li>

<li>scalar functions with axis [<a href="chapter5.html#scalar-functions-with-axis">1</a>]</li>

<li>scan (<code>\</code>) [<a href="chapter5.html#scan">1</a>]

<ul>

<li>with Boolean functions [<a href="chapter6.html#boolean-functions">1</a>]</li>

</ul></li>

<li>scatter indexing [<a href="appendixF.html#indexing">1</a>]</li>

<li>scientific notation [<a href="chapter7.html#format-by-specification">1</a>]</li>

<li>search for items in an array [<a href="chapter6.html#index-of">1</a>]</li>

<li>selecting unique items from a vector [<a href="chapter6.html#index-of">1</a>]</li>

<li>selection of data in an array

<ul>

<li>with first (<code>↑</code>) [<a href="chapter2.html#selecting-items-from-a-vector-first">1</a>]</li>

<li>with index (<code>[]</code>) [<a href="chapter2.html#selecting-items-from-a-vector-indexing">1</a>]</li>

</ul></li>

<li>selective assignment [<a href="chapter2.html#replacing-items-in-a-vector-selective-assignment">1</a>, <a href="chapter6.html#section-6.2-selecting-subsets-of-arrays">2</a>, <a href="chapter6.html#selective-assignment">3</a>]</li>

<li>shadowed names [<a href="chapter3.html#local-names">1</a>]</li>

<li>shape (<code>⍴</code>) [<a href="chapter2.html#measuring-the-size-of-a-vector-shape">1</a>]

<ul>

<li>of an array [<a href="chapter5.html#shape">1</a>]</li>

<li>of an empty array [<a href="chapter5.html#shape">1</a>]</li>

<li>relationship to reshape (<code>⍴</code>) [<a href="chapter5.html#shape">1</a>]</li>

<li>symbol <code>⍴</code> [<a href="chapter5.html#shape">1</a>]</li>

<li>to determine rank of an array [<a href="chapter5.html#rank">1</a>]</li>

</ul></li>

<li>shape of an array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>shared names [<a href="postscript.html#shared-variables">1</a>]</li>

<li>shared variables [<a href="postscript.html#shared-variables">1</a>]</li>

<li>signum (<code>×</code>) [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>]

<ul>

<li>relationship to magnitude (<code>∣</code>) [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>]</li>

</ul></li>

<li>simple array [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>simple scalar [<a href="chapter1.html#terms-for-data">1</a>, <a href="chapter5.html#section-5.1-properties-of-arrays">2</a>]

<ul>

<li>depth of [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

</ul></li>

<li>simple vector [<a href="chapter1.html#terms-for-data">1</a>]</li>

<li>simple versus nested array [<a href="chapter1.html#terms-for-data">1</a>]</li>

<li>sine hyperbolic [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>singular matrix [<a href="chapter6.html#matrix-inverse">1</a>]</li>

<li>slash (<code>/</code>)

<ul>

<li>not used for division [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

</ul></li>

<li>sort items in an array [<a href="chapter6.html#grade-up-and-grade-down">1</a>]</li>

<li>spaces

<ul>

<li>not used to separate groups of digits [<a href="chapter1.html#numbers">1</a>]</li>

<li>redundant [<a href="chapter1.html#use-of-blanks">1</a>]</li>

<li>used in display to indicate data grouping [<a href="chapter1.html#thinking-arrays">1</a>]</li>

<li>used to separate items in an array [<a href="chapter1.html#section-1.2-arithmetic-on-arrays">1</a>]</li>

</ul></li>

<li>square root [<a href="chapter6.html#power-and-exponential">1</a>]</li>

<li>state indicator [<a href="chapter4.html#seeing-the-state-indicator-sis">1</a>]

<ul>

<li>command for [<a href="chapter1.html#clearing-errors">1</a>, <a href="chapter4.html#seeing-the-state-indicator-sis">2</a>]</li>

<li>in debugging [<a href="chapter7.html#attention">1</a>]</li>

<li>interrupted function in [<a href="chapter4.html#seeing-the-state-indicator-sis">1</a>]</li>

<li>right arrow (<code>→</code>) to clear [<a href="chapter4.html#seeing-the-state-indicator-sis">1</a>]</li>

</ul></li>

<li>state indicator with statements <code>)SIS</code> [<a href="chapter1.html#clearing-errors">1</a>]</li>

<ul>

<li>with <code>)CONTINUE</code> [<a href="chapter1.html#section-1.5-saving-your-work">1</a>]</li>

</ul></li>

<li>stop facility [<a href="chapter7.html#stopping-where-you-choose">1</a>]</li>

<li>stopping execution [<a href="chapter7.html#stopping-where-you-choose">1</a>]</li>

<li>stopping your program [<a href="chapter7.html#stopping-your-program">1</a>, <a href="chapter7.html#stopping-where-you-choose">2</a>]</li>

<li>structured programming [<a href="chapter7.html#section-7.6-control-of-execution-iteration">1</a>]</li>

<li>subtraction (<code>−</code>) [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

<li>summation [<a href="chapter1.html#adding-up-numbers">1</a>]</li>

<li>symbol <code>,</code> [<a href="chapter2.html#joining-vectors-catenate">1</a>, <a href="chapter2.html#section-2.2-character-data">2</a>, <a href="chapter5.html#ravel">3</a>, <a href="chapter6.html#relational-functions">4</a>, <a href="chapter6.html#boolean-functions">5</a>]</li>

<li>symbol <code>.</code> [<a href="chapter5.html#inner-product">1</a>]</li>

<li>symbol <code><</code> [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>symbol <code>+</code> [<a href="chapter1.html#simple-arithmetic">1</a>]</li>

<li>symbol <code>+/</code> [<a href="chapter1.html#adding-up-numbers">1</a>]</li>

<li>symbol <code>⋆</code> [<a href="chapter2.html#scalar-function-power">1</a>]</li>

<li>symbol <code>/</code> [<a href="chapter1.html#adding-up-numbers">1</a>, <a href="chapter5.html#n-wise-reduction">2</a>, <a href="chapter6.html#selecting-items-with-a-mask-replication">3</a>]</li>

<li>symbol <code>/[]</code> [<a href="chapter5.html#reduction-with-axis">1</a>, <a href="chapter6.html#selecting-items-with-a-mask-replication">2</a>]</li>

<li>symbol <code>></code> [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>symbol <code>?</code> [<a href="chapter6.html#section-6.5-generating-random-numbers">1</a>]</li>

<li>symbol <code>∧</code> [<a href="chapter1.html#types-of-errors">1</a>, <a href="chapter6.html#boolean-functions">2</a>]</li>

<li>symbol <code>¨</code> [<a href="chapter3.html#each">1</a>]</li>

<li>symbol <code>⍷</code> [<a href="chapter6.html#find">1</a>]</li>

<li>symbol <code>∨</code> [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>symbol <code>=</code> [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>symbol <code>∼</code> [<a href="chapter6.html#boolean-functions">1</a>, <a href="chapter6.html#without">2</a>]</li>

<li>symbol <code>↑</code> [<a href="chapter2.html#selecting-items-from-a-vector-first">1</a>, <a href="chapter2.html#selecting-items-from-a-vector-take">2</a>, <a href="chapter5.html#first">3</a>]</li>

<li>symbol <code>↑[]</code> [<a href="chapter5.html#take-and-drop-with-axis">1</a>]</li>

<li>symbol <code>↓</code> [<a href="chapter2.html#selecting-items-from-a-vector-drop">1</a>]</li>

<li>symbol <code>↓[]</code> [<a href="chapter5.html#take-and-drop-with-axis">1</a>]</li>

<li>symbol <code>≤</code> [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>symbol <code>⌈</code> [<a href="chapter2.html#scalar-functions-maximum-and-minimum">1</a>, <a href="chapter2.html#scalar-functions-floor-and-ceiling">2</a>]</li>

<li>symbol <code>⌈/</code> [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>symbol <code>⌊</code> [<a href="chapter2.html#scalar-functions-maximum-and-minimum">1</a>, <a href="chapter2.html#scalar-functions-floor-and-ceiling">2</a>]</li>

<li>symbol <code>⌊/</code> [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>symbol <code>→</code> [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>symbol <code>⊃</code> [<a href="chapter2.html#selecting-items-from-a-vector-pick">1</a>, <a href="chapter5.html#nested-reshaping-of-an-array-disclose">2</a>, <a href="chapter5.html#pick">3</a>]</li>

<li>symbol <code>⊃¨</code> [<a href="chapter3.html#each">1</a>]</li>

<li>symbol <code>⊃[]</code> [<a href="chapter5.html#disclose-with-axis">1</a>]</li>

<li>symbol <code>⊂</code> [<a href="chapter5.html#nested-reshaping-of-an-array-enclose">1</a>, <a href="appendixF.html#partition">2</a>]</li>

<li>symbol <code>⊂[]</code> [<a href="chapter5.html#enclose-with-axis">1</a>]</li>

<li>symbol <code>○</code> [<a href="chapter6.html#trigonometric-functions">1</a>]</li>

<li>symbol <code>←</code> [<a href="chapter1.html#assignment">1</a>]</li>

<li>symbol <code>¯</code>

<ul>

<li>meaning of [<a href="chapter1.html#numbers">1</a>]</li>

</ul></li>

<li>symbol <code>⊥</code> [<a href="chapter6.html#decode">1</a>]</li>

<li>symbol <code>[]</code> [<a href="chapter2.html#selecting-items-from-a-vector-indexing">1</a>, <a href="chapter5.html#catenate-with-axis">2</a>, <a href="chapter5.html#ravel-with-axis">3</a>, <a href="chapter6.html#indexing">4</a>]</li>

<li>symbol <code>≥</code> [<a href="chapter6.html#relational-functions">1</a>]</li>

<li>symbol <code>∘.</code> [<a href="chapter5.html#outer-product">1</a>]</li>

<li>symbol <code>∊</code> [<a href="chapter5.html#enlist">1</a>, <a href="chapter6.html#membership">2</a>]</li>

<li>symbol <code>⍳</code> [<a href="chapter2.html#producing-consecutive-integers-interval">1</a>, <a href="chapter6.html#index-of">2</a>]</li>

<li>symbol <code>⍳¨</code> [<a href="chapter3.html#each">1</a>]</li>

<li>symbol <code>⍴</code> [<a href="chapter2.html#measuring-the-size-of-a-vector-shape">1</a>, <a href="chapter5.html#reshape">2</a>]</li>

<li>symbol <code>×</code> [<a href="chapter1.html#simple-arithmetic">1</a>, <a href="chapter2.html#scalar-functions-magnitude-and-direction">2</a>, <a href="chapter6.html#power-and-exponential">3</a>]</li>

<li>symbol <code>×/</code> [<a href="chapter3.html#reduction-on-vectors">1</a>]</li>

<li>symbol <code>\</code> [<a href="chapter5.html#scan">1</a>, <a href="chapter6.html#selecting-items-with-a-mask-expansion">2</a>]</li>

<li>symbol <code>÷</code> [<a href="chapter1.html#simple-arithmetic">1</a>, <a href="chapter2.html#scalar-functions-residue-and-reciprocal">2</a>]</li>

<li>symbol <code>∇</code> [<a href="chapter3.html#defined-function-structure">1</a>, <a href="appendixB.html#displaying-an-existing-definition">2</a>]</li>

<li>symbol <code>⊤</code> [<a href="chapter6.html#encode">1</a>]</li>

<li>symbol <code>∣</code> [<a href="chapter2.html#scalar-functions-magnitude-and-direction">1</a>, <a href="chapter2.html#scalar-functions-residue-and-reciprocal">2</a>]</li>

<li>symbol <code>⍲</code> [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>symbol <code>⍱</code> [<a href="chapter6.html#boolean-functions">1</a>]</li>

<li>symbol <code>⌷</code> [<a href="appendixF.html#indexing">1</a>]</li>

<li>symbol <code>⌽</code> [<a href="chapter6.html#reverse">1</a>, <a href="chapter6.html#rotate">2</a>]</li>

<li>symbol <code>⌽[]</code> [<a href="chapter6.html#reverse">1</a>]</li>

<li>symbol <code>⍉</code> [<a href="chapter6.html#transpose">1</a>]</li>

<li>symbol <code>!</code>) [<a href="chapter6.html#factorial-and-binomial">1</a>]</li>

<li>symbol <code>⍒</code> [<a href="chapter6.html#grade-up-and-grade-down">1</a>]</li>

<li>symbol <code>⍋</code> [<a href="chapter6.html#grade-up-and-grade-down">1</a>]</li>

<li>symbol <code>⍝</code> [<a href="chapter3.html#defined-function-structure">1</a>, <a href="chapter3.html#comments">2</a>, <a href="chapter3.html#good-apl2-programming-practices">3</a>]</li>

<li>symbol <code>≡</code> [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>, <a href="chapter5.html#depth">2</a>, <a href="chapter6.html#match">3</a>]</li>

<li>symbols

<ul>

<li>used in names [<a href="chapter1.html#names">1</a>]</li>

</ul></li>

<li>symbol <code>S∆</code> [<a href="chapter7.html#stopping-where-you-choose">1</a>]</li>

<li>symbol <code>T∆</code> [<a href="chapter7.html#tracing-execution">1</a>]</li>

<li>symbol <code>⍀</code> [<a href="chapter5.html#scan">1</a>, <a href="chapter6.html#selecting-items-with-a-mask-expansion">2</a>]</li>

<li>symbol <code>⊖</code> [<a href="chapter6.html#reverse">1</a>, <a href="chapter6.html#rotate">2</a>]</li>

<li>symbol <code>⍟</code> [<a href="chapter6.html#logarithm">1</a>]</li>

<li>symbol <code>⍎</code> [<a href="chapter7.html#executing-character-input">1</a>]</li>

<li>syntax

<ul>

<li>of headers [<a href="chapter3.html#header-syntax">1</a>]</li>

</ul></li>

<li><code>SYNTAX ERROR</code> [<a href="chapter1.html#types-of-errors">1</a>]</li>

<li>system command

<ul>

<li><code>)CLEAR</code> [<a href="chapter4.html#section-4.2-the-active-workspace">1</a>]</li>

<li><code>)CONTINUE</code> [<a href="chapter1.html#section-1.5-saving-your-work">1</a>]</li>

<li><code>)EDITOR</code> [<a href="appendixB.html#selecting-an-editor">1</a>]</li>

<li><code>)ERASE</code> [<a href="chapter4.html#removing-objects-from-the-active-workspace-erase">1</a>]</li>

<li><code>)PCOPY</code> [<a href="chapter4.html#adding-to-the-contents-of-the-active-workspace-copy-and-pcopy">1</a>]</li>

<li><code>)RESET</code> [<a href="chapter1.html#clearing-errors">1</a>]</li>

</ul></li>

<li>system functions [<a href="postscript.html#system-functions-and-system-variables">1</a>]</li>

<li>system variables [<a href="postscript.html#system-functions-and-system-variables">1</a>]</li>

<ul>

<li>See trace facility</li>

</ul></li>

<li>table [<a href="chapter5.html#section-5.1-properties-of-arrays">1</a>]</li>

<li>tangent [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>tangent hyperbolic [<a href="chapter6.html#circular-functions">1</a>]</li>

<li>termination of execution [<a href="chapter7.html#branch-in-a-program">1</a>]</li>

<li>times-reduction (<code>×/</code>) [<a href="chapter3.html#naming-derived-functions">1</a>]

<ul>

<li>to calculate count of an array [<a href="chapter5.html#count">1</a>]</li>

</ul></li>

<li>top-down programming [<a href="chapter8.html#building-and-maintaining-the-magazine-matrix">1</a>]</li>

<li>tower of Hanoi [<a href="chapter7.html#tower-of-hanoi">1</a>]</li>

<li>trace facility [<a href="chapter7.html#tracing-execution">1</a>]</li>

<li>tracing execution [<a href="chapter7.html#tracing-execution">1</a>]</li>

<li>transfer file [<a href="chapter4.html#moving-apl2-objects-between-computers-in-and-out">1</a>]</li>

<li>transpose (<code>⍉</code>) [<a href="chapter6.html#transpose">1</a>]</li>

<li>trapping of errors [<a href="postscript.html#event-handling">1</a>]</li>

<li>trigonometric function [<a href="chapter6.html#trigonometric-functions">1</a>]