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| author | Raymond Hettinger <rhettinger@users.noreply.github.com> | 2024-06-01 16:30:24 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-06-01 16:30:24 (GMT) |
| commit | 63111bfcf021db29ce6ef9ffa4117ffb7a2cb868 (patch) | |
| tree | 0a89ee9b9f489d9253dfb526ad9d15bae384e951 /Doc | |
| parent | 7dc745d1f5d9558047a52cad5e01df7567533269 (diff) | |
| download | cpython-63111bfcf021db29ce6ef9ffa4117ffb7a2cb868.zip cpython-63111bfcf021db29ce6ef9ffa4117ffb7a2cb868.tar.gz cpython-63111bfcf021db29ce6ef9ffa4117ffb7a2cb868.tar.bz2 | |
Add unique() recipe to itertools docs (gh-119911)
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/itertools.rst | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst index 121bfd3..3dc3f60 100644 --- a/Doc/library/itertools.rst +++ b/Doc/library/itertools.rst @@ -857,7 +857,7 @@ and :term:`generators <generator>` which incur interpreter overhead. return len(take(2, groupby(iterable, key))) <= 1 def unique_justseen(iterable, key=None): - "List unique elements, preserving order. Remember only the element just seen." + "Yield unique elements, preserving order. Remember only the element just seen." # unique_justseen('AAAABBBCCDAABBB') → A B C D A B # unique_justseen('ABBcCAD', str.casefold) → A B c A D if key is None: @@ -865,7 +865,7 @@ and :term:`generators <generator>` which incur interpreter overhead. return map(next, map(operator.itemgetter(1), groupby(iterable, key))) def unique_everseen(iterable, key=None): - "List unique elements, preserving order. Remember all elements ever seen." + "Yield unique elements, preserving order. Remember all elements ever seen." # unique_everseen('AAAABBBCCDAABBB') → A B C D # unique_everseen('ABBcCAD', str.casefold) → A B c D seen = set() @@ -880,6 +880,11 @@ and :term:`generators <generator>` which incur interpreter overhead. seen.add(k) yield element + def unique(iterable, key=None, reverse=False): + "Yield unique elements in sorted order. Supports unhashable inputs." + # unique([[1, 2], [3, 4], [1, 2]]) → [1, 2] [3, 4] + return unique_justseen(sorted(iterable, key=key, reverse=reverse), key=key) + def sliding_window(iterable, n): "Collect data into overlapping fixed-length chunks or blocks." # sliding_window('ABCDEFG', 4) → ABCD BCDE CDEF DEFG @@ -1605,6 +1610,13 @@ The following recipes have a more mathematical flavor: >>> ''.join(input_iterator) 'AAABBBCCDAABBB' + >>> list(unique([[1, 2], [3, 4], [1, 2]])) + [[1, 2], [3, 4]] + >>> list(unique('ABBcCAD', str.casefold)) + ['A', 'B', 'c', 'D'] + >>> list(unique('ABBcCAD', str.casefold, reverse=True)) + ['D', 'c', 'B', 'A'] + >>> d = dict(a=1, b=2, c=3) >>> it = iter_except(d.popitem, KeyError) >>> d['d'] = 4 |