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Merged
rhettinger merged 15 commits into from
Oct 18, 2022
Merged

General improvements to the itertools docs #98408

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9a81333
Remove distracting and wordy logostic_map example.
rhettinger Oct 18, 2022
655e624
Make the groupby() code equivalent more readable
rhettinger Oct 18, 2022
b1a632a
Break islice() docs into smaller paragraphs
rhettinger Oct 18, 2022
f874f0c
Minor wording improvements for the combinatoric iterators
rhettinger Oct 18, 2022
2cd06a0
Remove redundant text covered by the example below.
rhettinger Oct 18, 2022
6e655d6
Break string of sentences into two paragraphs
rhettinger Oct 18, 2022
62f4ff6
Remove unnecessary words in tee() docs
rhettinger Oct 18, 2022
81e294a
Improve iter_index() recipe to handle non-sequence iterable inputs
rhettinger Oct 18, 2022
78d49a4
Describe the purpose of the recipes section
rhettinger Oct 18, 2022
3019dfc
Note better alternative for unique_everseen()
rhettinger Oct 18, 2022
256bb59
Missing article
rhettinger Oct 18, 2022
ac0cc45
Markup
rhettinger Oct 18, 2022
78f0586
Add imports for the new doctests
rhettinger Oct 18, 2022
1dff762
Doctest the example
rhettinger Oct 18, 2022
5138ddd
Sphinx requires an actual unicode em dash
rhettinger Oct 18, 2022
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Improve iter_index() recipe to handle non-sequence iterable inputs
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@rhettinger
rhettinger committed Oct 18, 2022
commit 81e294a5033225c75e56bdf07a4a7802da50a049
36 changes: 29 additions & 7 deletions Doc/library/itertools.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -844,15 +844,25 @@ which incur interpreter overhead.
for k in range(len(roots) + 1)
]

def iter_index(seq, value, start=0):
"Return indices where a value occurs in a sequence."
def iter_index(iterable, value, start=0):
"Return indices where a value occurs in a sequence or iterable."
# iter_index('AABCADEAF', 'A') --> 0 1 4 7
i = start - 1
try:
while True:
yield (i := seq.index(value, i+1))
except ValueError:
pass
seq_index = iterable.index
except AttributeError:
# Slow path for general iterables
it = islice(iterable, start, None)
for i, element in enumerate(it, start):
if element is value or element == value:
yield i
else:
# Fast path for sequences
i = start - 1
try:
while True:
yield (i := seq_index(value, i+1))
except ValueError:
pass

def sieve(n):
"Primes less than n"
Expand Down Expand Up @@ -1192,6 +1202,18 @@ which incur interpreter overhead.
[]
>>> list(iter_index('', 'X'))
[]
>>> list(iter_index('AABCADEAF', 'A', 1))
[1, 4, 7]
>>> list(iter_index(iter('AABCADEAF'), 'A', 1))
[1, 4, 7]
>>> list(iter_index('AABCADEAF', 'A', 2))
[4, 7]
>>> list(iter_index(iter('AABCADEAF'), 'A', 2))
[4, 7]
>>> list(iter_index('AABCADEAF', 'A', 10))
[]
>>> list(iter_index(iter('AABCADEAF'), 'A', 10))
[]

>>> list(sieve(30))
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
Expand Down