Thanks to visit codestin.com
Credit goes to github.com

Skip to content

Misc cleanups and wording improvements for the itertools docs #119626

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 16 commits into from
May 27, 2024
Merged

Misc cleanups and wording improvements for the itertools docs #119626

Changes from 1 commit
Commits
Show all changes
16 commits
Select commit Hold shift + click to select a range
e42bf24
Tighten the wording for permutations(). Add links.
rhettinger May 25, 2024
2c2bb68
Tighten the wording for combinations(). Add links.
rhettinger May 25, 2024
269b506
Tighten the wording for combinations_with_replacement().
rhettinger May 25, 2024
642e89f
Tighen wording for islice()
rhettinger May 25, 2024
c581a38
Swap sentence order
rhettinger May 26, 2024
598c414
.
rhettinger May 26, 2024
a558705
Sync table examples with main docs
rhettinger May 27, 2024
2974acd
Improve readability of the amortization example
rhettinger May 27, 2024
295baa4
Improve accumulate() docs
rhettinger May 27, 2024
d3e6800
.
rhettinger May 27, 2024
1f52c89
Improve wording for compress()
rhettinger May 27, 2024
95f503b
Improve wording for count()
rhettinger May 27, 2024
61f629d
Tighter wording for cycle()
rhettinger May 27, 2024
95e82ed
Improve wording for dropwhile()
rhettinger May 27, 2024
6cfce87
Misc wording tweaks
rhettinger May 27, 2024
d60c375
Tweak starmap() wording
rhettinger May 27, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Next Next commit
Tighten the wording for combinations(). Add links.
  • Loading branch information
@rhettinger
rhettinger committed May 25, 2024
commit 2c2bb689a5db23f62e76a20863638fb656111127
26 changes: 9 additions & 17 deletions Doc/library/itertools.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -230,12 +230,17 @@ loops that truncate the stream.

Return *r* length subsequences of elements from the input *iterable*.

The output is a subsequence of :func:`product` keeping only entries that
are subsequences of the *iterable*. The length of the output is given
by :func:`math.comb` which computes ``n! / r! / (n - r)!`` when ``0 ≤ r
≤ n`` or zero when ``r > n``.

The combination tuples are emitted in lexicographic order according to
the order of the input *iterable*. So, if the input *iterable* is sorted,
the order of the input *iterable*. If the input *iterable* is sorted,
the output tuples will be produced in sorted order.

Elements are treated as unique based on their position, not on their
value. So, if the input elements are unique, there will be no repeated
value. If the input elements are unique, there will be no repeated
values within each combination.

Roughly equivalent to::
Expand All @@ -260,19 +265,6 @@ loops that truncate the stream.
indices[j] = indices[j-1] + 1
yield tuple(pool[i] for i in indices)

The code for :func:`combinations` can be also expressed as a subsequence
of :func:`permutations` after filtering entries where the elements are not
in sorted order (according to their position in the input pool)::

def combinations(iterable, r):
pool = tuple(iterable)
n = len(pool)
for indices in permutations(range(n), r):
if sorted(indices) == list(indices):
yield tuple(pool[i] for i in indices)

The number of items returned is ``n! / r! / (n-r)!`` when ``0 <= r <= n``
or zero when ``r > n``.

.. function:: combinations_with_replacement(iterable, r)

Expand Down Expand Up @@ -543,8 +535,8 @@ loops that truncate the stream.

The output is a subsequence of :func:`product` where entries with
repeated elements have been filtered out. The length of the output is
given by :func:`math.perm` which gives ``n! / (n-r)!`` when ``0 <= r <=
n`` or zero when ``r > n``.
given by :func:`math.perm` which computes ``n! / (n - r)!`` when
``0 ≤ r ≤ n`` or zero when ``r > n``.

The permutation tuples are emitted in lexicographic order according to
the order of the input *iterable*. If the input *iterable* is sorted,
Expand Down