💾 Archived View for gem.sdf.org › s.kaplan › cheatsheets › programming-languages › ruby.md captured on 2024-08-18 at 18:18:47.

-=-=-=-=-=-=-

# Ruby Cheatsheet

## Unique Features
- Dynamic, object-oriented language
- Interpreted with garbage collection
- Duck typing
- Blocks and Procs
- Mixins
- RubyGems package manager

## Variables

Local variable

x = 5

Instance variable

@name = "John"

Class variable

@@count = 0

Global variable

$debug = true


## Functions

Method definition

def say_hello(name)

puts "Hello, #{name}!"

end

Method call

say_hello("Ruby")


## Loops

While loop

while x < 10 do

puts x

x += 1

end

For loop

for i in 0..5

puts i

end

Each iterator

(1..5).each do |i|

puts i

end


## Conditionals

If statement

if x > 5

puts "x is greater than 5"

elsif x == 5

puts "x is equal to 5"

else

puts "x is less than 5"

end

Ternary operator

x > 5 ? "x is greater than 5" : "x is less than or equal to 5"


## File Manipulation

Open file

file = File.open("filename.txt", "r")

Read file

contents = file.read

Close file

file.close

Write to file

File.open("filename.txt", "w") do |file|

file.write("Hello, world!")

end


## Resources
- [Ruby Documentation](https://www.ruby-lang.org/en/documentation/)
- [RubyGems](https://rubygems.org/)
- [Ruby on Rails](https://rubyonrails.org/)