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author | Raymond Hettinger <python@rcn.com> | 2003-06-18 19:25:37 (GMT) |
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committer | Raymond Hettinger <python@rcn.com> | 2003-06-18 19:25:37 (GMT) |
commit | befa37dd05050ecce9637d81ebe9d8d74688129c (patch) | |
tree | 904725503d82dda010c10fecb8bb6327d98c9c4d /Lib/test/test_itertools.py | |
parent | 3a8fbe7eeca4cc8cb944c8120690e54a6c775747 (diff) | |
download | cpython-befa37dd05050ecce9637d81ebe9d8d74688129c.zip cpython-befa37dd05050ecce9637d81ebe9d8d74688129c.tar.gz cpython-befa37dd05050ecce9637d81ebe9d8d74688129c.tar.bz2 |
Minor updates:
* Updated comment on design of imap()
* Added untraversed object in izip() structure
* Replaced the pairwise() example with a more general window() example
Diffstat (limited to 'Lib/test/test_itertools.py')
-rw-r--r-- | Lib/test/test_itertools.py | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py index a4ad845..846a690 100644 --- a/Lib/test/test_itertools.py +++ b/Lib/test/test_itertools.py @@ -427,10 +427,6 @@ Samuele ... "Returns True if pred(x) is False for every element in the iterable" ... return not nth(ifilter(pred, seq), 0) ->>> def pairwise(seq): -... "s -> (s0,s1), (s1,s2), (s2, s3), ..." -... return izip(seq, islice(seq,1,len(seq))) - >>> def padnone(seq): ... "Returns the sequence elements and then returns None indefinitely" ... return chain(seq, repeat(None)) @@ -442,6 +438,16 @@ Samuele >>> def dotproduct(vec1, vec2): ... return sum(imap(operator.mul, vec1, vec2)) +>>> def window(seq, n=2): +... "Returns a sliding window (of width n) over data from the iterable" +... " s -> (s0,s1,...s[n-1]), (s1,s2,...,sn), ... " +... it = iter(seq) +... result = tuple(islice(it, n)) +... if len(result) == n: +... yield result +... for elem in it: +... result = result[1:] + (elem,) +... yield result This is not part of the examples but it tests to make sure the definitions perform as purported. @@ -473,9 +479,12 @@ True >>> no(lambda x: x%2==0, [1, 2, 5, 9]) False ->>> list(pairwise('abc')) +>>> list(window('abc')) [('a', 'b'), ('b', 'c')] +>>> list(window('abc',5)) +[] + >>> list(islice(padnone('abc'), 0, 6)) ['a', 'b', 'c', None, None, None] |