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queue

A multi-producer, multi-consumer queue.

Classes

Empty

Exception raised by Queue.get(block=0)/get_nowait().
with_traceback(...)

  Exception.with_traceback(tb) --
      set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>

Full

Exception raised by Queue.put(block=0)/put_nowait().
with_traceback(...)

  Exception.with_traceback(tb) --
      set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>

LifoQueue

Variant of Queue that retrieves most recently added entries first.
empty(self)

  Return True if the queue is empty, False otherwise (not reliable!).

          This method is likely to be removed at some point.  Use qsize() == 0
          as a direct substitute, but be aware that either approach risks a race
          condition where a queue can grow before the result of empty() or
          qsize() can be used.

          To create code that needs to wait for all queued tasks to be
          completed, the preferred technique is to use the join() method.
        
full(self)

  Return True if the queue is full, False otherwise (not reliable!).

          This method is likely to be removed at some point.  Use qsize() >= n
          as a direct substitute, but be aware that either approach risks a race
          condition where a queue can shrink before the result of full() or
          qsize() can be used.
        
get(self, block=True, timeout=None)

  Remove and return an item from the queue.

          If optional args 'block' is true and 'timeout' is None (the default),
          block if necessary until an item is available. If 'timeout' is
          a non-negative number, it blocks at most 'timeout' seconds and raises
          the Empty exception if no item was available within that time.
          Otherwise ('block' is false), return an item if one is immediately
          available, else raise the Empty exception ('timeout' is ignored
          in that case).
        
get_nowait(self)

  Remove and return an item from the queue without blocking.

          Only get an item if one is immediately available. Otherwise
          raise the Empty exception.
        
join(self)

  Blocks until all items in the Queue have been gotten and processed.

          The count of unfinished tasks goes up whenever an item is added to the
          queue. The count goes down whenever a consumer thread calls task_done()
          to indicate the item was retrieved and all work on it is complete.

          When the count of unfinished tasks drops to zero, join() unblocks.
        
put(self, item, block=True, timeout=None)

  Put an item into the queue.

          If optional args 'block' is true and 'timeout' is None (the default),
          block if necessary until a free slot is available. If 'timeout' is
          a non-negative number, it blocks at most 'timeout' seconds and raises
          the Full exception if no free slot was available within that time.
          Otherwise ('block' is false), put an item on the queue if a free slot
          is immediately available, else raise the Full exception ('timeout'
          is ignored in that case).
        
put_nowait(self, item)

  Put an item into the queue without blocking.

          Only enqueue the item if a free slot is immediately available.
          Otherwise raise the Full exception.
        
qsize(self)

  Return the approximate size of the queue (not reliable!).
task_done(self)

  Indicate that a formerly enqueued task is complete.

          Used by Queue consumer threads.  For each get() used to fetch a task,
          a subsequent call to task_done() tells the queue that the processing
          on the task is complete.

          If a join() is currently blocking, it will resume when all items
          have been processed (meaning that a task_done() call was received
          for every item that had been put() into the queue).

          Raises a ValueError if called more times than there were items
          placed in the queue.
        

PriorityQueue

Variant of Queue that retrieves open entries in priority order (lowest first).

    Entries are typically tuples of the form:  (priority number, data).
    
empty(self)

  Return True if the queue is empty, False otherwise (not reliable!).

          This method is likely to be removed at some point.  Use qsize() == 0
          as a direct substitute, but be aware that either approach risks a race
          condition where a queue can grow before the result of empty() or
          qsize() can be used.

          To create code that needs to wait for all queued tasks to be
          completed, the preferred technique is to use the join() method.
        
full(self)

  Return True if the queue is full, False otherwise (not reliable!).

          This method is likely to be removed at some point.  Use qsize() >= n
          as a direct substitute, but be aware that either approach risks a race
          condition where a queue can shrink before the result of full() or
          qsize() can be used.
        
get(self, block=True, timeout=None)

  Remove and return an item from the queue.

          If optional args 'block' is true and 'timeout' is None (the default),
          block if necessary until an item is available. If 'timeout' is
          a non-negative number, it blocks at most 'timeout' seconds and raises
          the Empty exception if no item was available within that time.
          Otherwise ('block' is false), return an item if one is immediately
          available, else raise the Empty exception ('timeout' is ignored
          in that case).
        
get_nowait(self)

  Remove and return an item from the queue without blocking.

          Only get an item if one is immediately available. Otherwise
          raise the Empty exception.
        
join(self)

  Blocks until all items in the Queue have been gotten and processed.

          The count of unfinished tasks goes up whenever an item is added to the
          queue. The count goes down whenever a consumer thread calls task_done()
          to indicate the item was retrieved and all work on it is complete.

          When the count of unfinished tasks drops to zero, join() unblocks.
        
put(self, item, block=True, timeout=None)

  Put an item into the queue.

          If optional args 'block' is true and 'timeout' is None (the default),
          block if necessary until a free slot is available. If 'timeout' is
          a non-negative number, it blocks at most 'timeout' seconds and raises
          the Full exception if no free slot was available within that time.
          Otherwise ('block' is false), put an item on the queue if a free slot
          is immediately available, else raise the Full exception ('timeout'
          is ignored in that case).
        
put_nowait(self, item)

  Put an item into the queue without blocking.

          Only enqueue the item if a free slot is immediately available.
          Otherwise raise the Full exception.
        
qsize(self)

  Return the approximate size of the queue (not reliable!).
task_done(self)

  Indicate that a formerly enqueued task is complete.

          Used by Queue consumer threads.  For each get() used to fetch a task,
          a subsequent call to task_done() tells the queue that the processing
          on the task is complete.

          If a join() is currently blocking, it will resume when all items
          have been processed (meaning that a task_done() call was received
          for every item that had been put() into the queue).

          Raises a ValueError if called more times than there were items
          placed in the queue.
        

Queue

Create a queue object with a given maximum size.

    If maxsize is <= 0, the queue size is infinite.
    
empty(self)

  Return True if the queue is empty, False otherwise (not reliable!).

          This method is likely to be removed at some point.  Use qsize() == 0
          as a direct substitute, but be aware that either approach risks a race
          condition where a queue can grow before the result of empty() or
          qsize() can be used.

          To create code that needs to wait for all queued tasks to be
          completed, the preferred technique is to use the join() method.
        
full(self)

  Return True if the queue is full, False otherwise (not reliable!).

          This method is likely to be removed at some point.  Use qsize() >= n
          as a direct substitute, but be aware that either approach risks a race
          condition where a queue can shrink before the result of full() or
          qsize() can be used.
        
get(self, block=True, timeout=None)

  Remove and return an item from the queue.

          If optional args 'block' is true and 'timeout' is None (the default),
          block if necessary until an item is available. If 'timeout' is
          a non-negative number, it blocks at most 'timeout' seconds and raises
          the Empty exception if no item was available within that time.
          Otherwise ('block' is false), return an item if one is immediately
          available, else raise the Empty exception ('timeout' is ignored
          in that case).
        
get_nowait(self)

  Remove and return an item from the queue without blocking.

          Only get an item if one is immediately available. Otherwise
          raise the Empty exception.
        
join(self)

  Blocks until all items in the Queue have been gotten and processed.

          The count of unfinished tasks goes up whenever an item is added to the
          queue. The count goes down whenever a consumer thread calls task_done()
          to indicate the item was retrieved and all work on it is complete.

          When the count of unfinished tasks drops to zero, join() unblocks.
        
put(self, item, block=True, timeout=None)

  Put an item into the queue.

          If optional args 'block' is true and 'timeout' is None (the default),
          block if necessary until a free slot is available. If 'timeout' is
          a non-negative number, it blocks at most 'timeout' seconds and raises
          the Full exception if no free slot was available within that time.
          Otherwise ('block' is false), put an item on the queue if a free slot
          is immediately available, else raise the Full exception ('timeout'
          is ignored in that case).
        
put_nowait(self, item)

  Put an item into the queue without blocking.

          Only enqueue the item if a free slot is immediately available.
          Otherwise raise the Full exception.
        
qsize(self)

  Return the approximate size of the queue (not reliable!).
task_done(self)

  Indicate that a formerly enqueued task is complete.

          Used by Queue consumer threads.  For each get() used to fetch a task,
          a subsequent call to task_done() tells the queue that the processing
          on the task is complete.

          If a join() is currently blocking, it will resume when all items
          have been processed (meaning that a task_done() call was received
          for every item that had been put() into the queue).

          Raises a ValueError if called more times than there were items
          placed in the queue.
        

SimpleQueue

Simple, unbounded, reentrant FIFO queue.
empty(self, /)

  Return True if the queue is empty, False otherwise (not reliable!).
get(self, /, block=True, timeout=None)

  Remove and return an item from the queue.

  If optional args 'block' is true and 'timeout' is None (the default),
  block if necessary until an item is available. If 'timeout' is
  a non-negative number, it blocks at most 'timeout' seconds and raises
  the Empty exception if no item was available within that time.
  Otherwise ('block' is false), return an item if one is immediately
  available, else raise the Empty exception ('timeout' is ignored
  in that case).
get_nowait(self, /)

  Remove and return an item from the queue without blocking.

  Only get an item if one is immediately available. Otherwise
  raise the Empty exception.
put(self, /, item, block=True, timeout=None)

  Put the item on the queue.

  The optional 'block' and 'timeout' arguments are ignored, as this method
  never blocks.  They are provided for compatibility with the Queue class.
put_nowait(self, /, item)

  Put an item into the queue without blocking.

  This is exactly equivalent to `put(item)` and is only provided
  for compatibility with the Queue class.
qsize(self, /)

  Return the approximate size of the queue (not reliable!).

deque

deque([iterable[, maxlen]]) --> deque object

A list-like sequence optimized for data accesses near its endpoints.
append(...)

  Add an element to the right side of the deque.
appendleft(...)

  Add an element to the left side of the deque.
clear(...)

  Remove all elements from the deque.
copy(...)

  Return a shallow copy of a deque.
count(...)

  D.count(value) -> integer -- return number of occurrences of value
extend(...)

  Extend the right side of the deque with elements from the iterable
extendleft(...)

  Extend the left side of the deque with elements from the iterable
index(...)

  D.index(value, [start, [stop]]) -> integer -- return first index of value.
  Raises ValueError if the value is not present.
insert(...)

  D.insert(index, object) -- insert object before index
pop(...)

  Remove and return the rightmost element.
popleft(...)

  Remove and return the leftmost element.
remove(...)

  D.remove(value) -- remove first occurrence of value.
reverse(...)

  D.reverse() -- reverse *IN PLACE*
rotate(...)

  Rotate the deque n steps to the right (default n=1).  If n is negative, rotates left.
maxlen = <attribute 'maxlen' of 'collections.deque' objects>
  maximum size of a deque or None if unbounded

Functions

heappop

heappop(heap, /)

  Pop the smallest item off the heap, maintaining the heap invariant.

heappush

heappush(heap, item, /)

  Push item onto heap, maintaining the heap invariant.

time

monotonic(...)

  monotonic() -> float

  Monotonic clock, cannot go backward.

Modules

threading

types