summaryrefslogtreecommitdiffstats
path: root/Doc
diff options
context:
space:
mode:
authorRaymond Hettinger <python@rcn.com>2010-04-02 06:23:12 (GMT)
committerRaymond Hettinger <python@rcn.com>2010-04-02 06:23:12 (GMT)
commitf28dd0d1bfd85e5285894bfac54f6668d7217210 (patch)
tree3dbec3d0189ef31f73680bc422ac9138a660138c /Doc
parent4bfd3bda2ea7e71219fffe8b3e36c818b590be16 (diff)
downloadcpython-f28dd0d1bfd85e5285894bfac54f6668d7217210.zip
cpython-f28dd0d1bfd85e5285894bfac54f6668d7217210.tar.gz
cpython-f28dd0d1bfd85e5285894bfac54f6668d7217210.tar.bz2
Cleanup itertools recipes
Diffstat (limited to 'Doc')
-rw-r--r--Doc/library/itertools.rst16
1 files changed, 8 insertions, 8 deletions
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index 663b93c..c914b53 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -697,7 +697,7 @@ which incur interpreter overhead.
def ncycles(iterable, n):
"Returns the sequence elements n times"
- return chain.from_iterable(repeat(iterable, n))
+ return chain.from_iterable(repeat(tuple(iterable), n))
def dotproduct(vec1, vec2):
return sum(imap(operator.mul, vec1, vec2))
@@ -794,23 +794,23 @@ which incur interpreter overhead.
def random_product(*args, **kwds):
"Random selection from itertools.product(*args, **kwds)"
pools = map(tuple, args) * kwds.get('repeat', 1)
- return map(random.choice, pools)
+ return tuple(random.choice(pool) for pool in pools)
def random_permuation(iterable, r=None):
"Random selection from itertools.permutations(iterable, r)"
- pool = list(iterable)
+ pool = tuple(iterable)
r = len(pool) if r is None else r
- return random.sample(pool, r)
+ return tuple(random.sample(pool, r))
def random_combination(iterable, r):
"Random selection from itertools.combinations(iterable, r)"
- pool = list(iterable)
- return sorted(random.sample(pool, r), key=pool.index)
+ pool = tuple(iterable)
+ return tuple(sorted(random.sample(pool, r), key=pool.index))
def random_combination_with_replacement(iterable, r):
"Random selection from itertools.combinations_with_replacement(iterable, r)"
- pool = list(iterable)
- return sorted(imap(random.choice, [pool]*r), key=pool.index)
+ pool = tuple(iterable)
+ return tuple(sorted(imap(random.choice, [pool]*r), key=pool.index))
Note, many of the above recipes can be optimized by replacing global lookups
with local variables defined as default values. For example, the