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aiostream
=========
.. image:: https://readthedocs.org/projects/aiostream/badge/?version=latest
:target: http://aiostream.readthedocs.io/en/latest/?badge=latest
:alt:
.. image:: https://coveralls.io/repos/github/vxgmichel/aiostream/badge.svg?branch=master
:target: https://coveralls.io/github/vxgmichel/aiostream?branch=master
:alt:
.. image:: https://travis-ci.org/vxgmichel/aiostream.svg?branch=master
:target: https://travis-ci.org/vxgmichel/aiostream
:alt:
.. image:: https://img.shields.io/pypi/v/aiostream.svg
:target: https://pypi.python.org/pypi/aiostream
:alt:
.. image:: https://img.shields.io/pypi/pyversions/aiostream.svg
:target: https://pypi.python.org/pypi/aiostream/
:alt:
Generator-based operators for asynchronous iteration
Synopsis
--------
aiostream_ provides a collection of stream operators that can be combined to create
asynchronous pipelines of operations.
It can be seen as an asynchronous version of itertools_, although some aspects are slightly different.
Essentially, all the provided operators return a unified interface called a stream.
A stream is an enhanced asynchronous iterable providing the following features:
- **Operator pipe-lining** - using pipe symbol ``|``
- **Repeatability** - every iteration creates a different iterator
- **Safe iteration context** - using ``async with`` and the ``stream`` method
- **Simplified execution** - get the last element from a stream using ``await``
- **Slicing and indexing** - using square brackets ``[]``
- **Concatenation** - using addition symbol ``+``
Requirements
------------
The stream operators rely heavily on asynchronous generators (`PEP 525`_):
- python >= 3.6
Stream operators
----------------
The `stream operators`_ are separated in 7 categories:
+--------------------+---------------------------------------------------------------------------------------+
| **creation** | iterate_, preserve_, just_, call_, empty_, throw_, never_, repeat_, count_, range_ |
+--------------------+---------------------------------------------------------------------------------------+
| **transformation** | map_, enumerate_, starmap_, cycle_, chunks_ |
+--------------------+---------------------------------------------------------------------------------------+
| **selection** | take_, takelast_, skip_, skiplast_, getitem_, filter_, until_, takewhile_, dropwhile_ |
+--------------------+---------------------------------------------------------------------------------------+
| **combination** | map_, zip_, merge_, chain_, ziplatest_ |
+--------------------+---------------------------------------------------------------------------------------+
| **aggregation** | accumulate_, reduce_, list_ |
+--------------------+---------------------------------------------------------------------------------------+
| **advanced** | concat_, flatten_, switch_, concatmap_, flatmap_, switchmap_ |
+--------------------+---------------------------------------------------------------------------------------+
| **timing** | spaceout_, timeout_, delay_ |
+--------------------+---------------------------------------------------------------------------------------+
| **miscellaneous** | action_, print_ |
+--------------------+---------------------------------------------------------------------------------------+
Demonstration
-------------
The following example demonstrates most of the streams capabilities:
.. sourcecode:: python
import asyncio
from aiostream import stream, pipe
async def main():
# Create a counting stream with a 0.2 seconds interval
xs = stream.count(interval=0.2)
# Operators can be piped using '|'
ys = xs | pipe.map(lambda x: x**2)
# Streams can be sliced
zs = ys[1:10:2]
# Use a stream context for proper resource management
async with zs.stream() as streamer:
# Asynchronous iteration
async for z in streamer:
# Print 1, 9, 25, 49 and 81
print('->', z)
# Streams can be awaited and return the last value
print('9² = ', await zs)
# Streams can run several times
print('9² = ', await zs)
# Streams can be concatenated
one_two_three = stream.just(1) + stream.range(2, 4)
# Print [1, 2, 3]
print(await stream.list(one_two_three))
# Run main coroutine
loop = asyncio.get_event_loop()
loop.run_until_complete(main())
loop.close()
More examples are available in the `example section`_ of the documentation.
Contact
-------
Vincent Michel: vxgmichel@gmail.com
.. _aiostream: https://github.com/vxgmichel/aiostream
.. _PEP 525: http://www.python.org/dev/peps/pep-0525/
.. _Rx: http://reactivex.io/
.. _aioreactive: http://github.com/dbrattli/aioreactive
.. _itertools: http://docs.python.org/3/library/itertools.html
.. _stream operators: http://aiostream.readthedocs.io/en/latest/operators.html
.. _example section: http://aiostream.readthedocs.io/en/latest/examples.html
.. _iterate: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.iterate
.. _preserve: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.preserve
.. _just: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.just
.. _call: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.call
.. _throw: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.throw
.. _empty: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.empty
.. _never: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.never
.. _repeat: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.repeat
.. _range: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.range
.. _count: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.count
.. _map: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.map
.. _enumerate: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.enumerate
.. _starmap: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.starmap
.. _cycle: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.cycle
.. _chunks: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.chunks
.. _take: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.take
.. _takelast: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.takelast
.. _skip: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.skip
.. _skiplast: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.skiplast
.. _getitem: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.getitem
.. _filter: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.filter
.. _until: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.until
.. _takewhile: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.takewhile
.. _dropwhile: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.dropwhile
.. _chain: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.chain
.. _zip: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.zip
.. _merge: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.merge
.. _ziplatest: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.ziplatest
.. _accumulate: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.accumulate
.. _reduce: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.reduce
.. _list: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.list
.. _concat: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.concat
.. _flatten: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.flatten
.. _switch: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.switch
.. _concatmap: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.concatmap
.. _flatmap: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.flatmap
.. _switchmap: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.switchmap
.. _spaceout: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.spaceout
.. _delay: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.delay
.. _timeout: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.timeout
.. _action: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.action
.. _print: http://aiostream.readthedocs.io/en/latest/operators.html#aiostream.stream.print
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