more-itertools 4.2.0

More routines for operating on iterables, beyond itertools

Python’s itertools library is a gem - you can compose elegant solutions for a variety of problems with the functions it provides. In more-itertools we collect additional building blocks, recipes, and routines for working with Python iterables.

Getting started

To get started, install the library with pip:

pip install more-itertools

The recipes from the itertools docs are included in the top-level package:

>>> from more_itertools import flatten
>>> iterable = [(0, 1), (2, 3)]
>>> list(flatten(iterable))
[0, 1, 2, 3]

Several new recipes are available as well:

>>> from more_itertools import chunked
>>> iterable = [0, 1, 2, 3, 4, 5, 6, 7, 8]
>>> list(chunked(iterable, 3))
[[0, 1, 2], [3, 4, 5], [6, 7, 8]]

>>> from more_itertools import spy
>>> iterable = (x * x for x in range(1, 6))
>>> head, iterable = spy(iterable, n=3)
>>> list(head)
[1, 4, 9]
>>> list(iterable)
[1, 4, 9, 16, 25]

For the full listing of functions, see the API documentation.

Development

more-itertools is maintained by @erikrose and @bbayles, with help from many others. If you have a problem or suggestion, please file a bug or pull request in this repository. Thanks for contributing!

Version History

4.2.0

• New itertools:

  • map_reduce (thanks to pylang)

  • prepend (from the Python 3.7 docs)

• Improvements to existing itertools:

  • bucket now complies with PEP 479 (thanks to irmen)

• Other changes:

  • Python 3.7 is now supported (thanks to irmen)

  • Python 3.3 is no longer supported

  • The test suite no longer requires third-party modules to run

  • The API docs now include links to source code

4.1.0

• New itertools:

  • split_at (thanks to michael-celani)

  • circular_shifts (thanks to hiqua)

  • make_decorator - see the blog post Yo, I heard you like decorators for a tour (thanks to pylang)

  • always_reversible (thanks to michael-celani)

  • nth_combination (from the Python 3.7 docs)

• Improvements to existing itertools:

  • seekable now has an elements method to return cached items.

  • The performance tradeoffs between roundrobin and interleave_longest are now documented (thanks michael-celani, pylang, and MSeifert04)

4.0.1

• No code changes - this release fixes how the docs display on PyPI.

4.0.0

• New itertools:

  • consecutive_groups (Based on the example in the Python 2.4 docs)

  • seekable (If you’re looking for how to “reset” an iterator, you’re in luck!)

  • exactly_n (thanks to michael-celani)

  • run_length.encode and run_length.decode

  • difference

• Improvements to existing itertools:

  • The number of items between filler elements in intersperse can now be specified (thanks to pylang)

  • distinct_permutations and peekable got some minor adjustments (thanks to MSeifert04)

  • always_iterable now returns an iterator object. It also now allows different types to be considered iterable (thanks to jaraco)

  • bucket can now limit the keys it stores in memory

  • one now allows for custom exceptions (thanks to kalekundert)

• Other changes:

  • A few typos were fixed (thanks to EdwardBetts)

  • All tests can now be run with python setup.py test

The major version update is due to the change in the return value of always_iterable. It now always returns iterator objects:

>>> from more_itertools import always_iterable
# Non-iterable objects are wrapped with iter(tuple(obj))
>>> always_iterable(12345)
<tuple_iterator object at 0x7fb24c9488d0>
>>> list(always_iterable(12345))
[12345]
# Iterable objects are wrapped with iter()
>>> always_iterable([1, 2, 3, 4, 5])
<list_iterator object at 0x7fb24c948c50>

3.2.0

• New itertools:

  • lstrip, rstrip, and strip (thanks to MSeifert04 and pylang)

  • islice_extended

• Improvements to existing itertools:

  • Some bugs with slicing peekable-wrapped iterables were fixed

3.1.0

• New itertools:

  • numeric_range (Thanks to BebeSparkelSparkel and MSeifert04)

  • count_cycle (Thanks to BebeSparkelSparkel)

  • locate (Thanks to pylang and MSeifert04)

• Improvements to existing itertools:

  • A few itertools are now slightly faster due to some function optimizations. (Thanks to MSeifert04)

• The docs have been substantially revised with installation notes, categories for library functions, links, and more. (Thanks to pylang)

3.0.0

• Removed itertools:

  • context has been removed due to a design flaw - see below for replacement options. (thanks to NeilGirdhar)

• Improvements to existing itertools:

  • side_effect now supports before and after keyword arguments. (Thanks to yardsale8)

• PyPy and PyPy3 are now supported.

The major version change is due to the removal of the context function. Replace it with standard with statement context management:

# Don't use context() anymore
file_obj = StringIO()
consume(print(x, file=f) for f in context(file_obj) for x in u'123')

# Use a with statement instead
file_obj = StringIO()
with file_obj as f:
    consume(print(x, file=f) for x in u'123')

2.6.0

• New itertools:

  • adjacent and groupby_transform (Thanks to diazona)

  • always_iterable (Thanks to jaraco)

  • (Removed in 3.0.0) context (Thanks to yardsale8)

  • divide (Thanks to mozbhearsum)

• Improvements to existing itertools:

  • ilen is now slightly faster. (Thanks to wbolster)

  • peekable can now prepend items to an iterable. (Thanks to diazona)

2.5.0

• New itertools:

  • distribute (Thanks to mozbhearsum and coady)

  • sort_together (Thanks to clintval)

  • stagger and zip_offset (Thanks to joshbode)

  • padded

• Improvements to existing itertools:

  • peekable now handles negative indexes and slices with negative components properly.

  • intersperse is now slightly faster. (Thanks to pylang)

  • windowed now accepts a step keyword argument. (Thanks to pylang)

• Python 3.6 is now supported.

2.4.1

• Move docs 100% to readthedocs.io.

2.4

• New itertools:

  • accumulate, all_equal, first_true, partition, and tail from the itertools documentation.

  • bucket (Thanks to Rosuav and cvrebert)

  • collapse (Thanks to abarnet)

  • interleave and interleave_longest (Thanks to abarnet)

  • side_effect (Thanks to nvie)

  • sliced (Thanks to j4mie and coady)

  • split_before and split_after (Thanks to astronouth7303)

  • spy (Thanks to themiurgo and mathieulongtin)

• Improvements to existing itertools:

  • chunked is now simpler and more friendly to garbage collection. (Contributed by coady, with thanks to piskvorky)

  • collate now delegates to heapq.merge when possible. (Thanks to kmike and julianpistorius)

  • peekable-wrapped iterables are now indexable and sliceable. Iterating through peekable-wrapped iterables is also faster.

  • one and unique_to_each have been simplified. (Thanks to coady)

2.3

• Added one from jaraco.util.itertools. (Thanks, jaraco!)

• Added distinct_permutations and unique_to_each. (Contributed by bbayles)

• Added windowed. (Contributed by bbayles, with thanks to buchanae, jaraco, and abarnert)

• Simplified the implementation of chunked. (Thanks, nvie!)

• Python 3.5 is now supported. Python 2.6 is no longer supported.

• Python 3 is now supported directly; there is no 2to3 step.

2.2

• Added iterate and with_iter. (Thanks, abarnert!)

2.1

• Added (tested!) implementations of the recipes from the itertools documentation. (Thanks, Chris Lonnen!)

• Added ilen. (Thanks for the inspiration, Matt Basta!)

2.0

• chunked now returns lists rather than tuples. After all, they’re homogeneous. This slightly backward-incompatible change is the reason for the major version bump.

• Added @consumer.

• Improved test machinery.

1.1

• Added first function.

• Added Python 3 support.

• Added a default arg to peekable.peek().

• Noted how to easily test whether a peekable iterator is exhausted.

• Rewrote documentation.

1.0

• Initial release, with collate, peekable, and chunked. Could really use better docs.