New submission from Vladimir Berkutov <dair.t...@gmail.com>:
It might be useful to introduce a new map() and filter() methods to iterators
and iterables. Both methods should accept lambda/function which transforms a
single argument into value. Both methods should return another iterator.
# proposed methods usage:
range(10).map(abs).filter(lambda x: x % 5 == 0)
# existing equivalent:
filter(lambda x: x % 5 == 0, map(abs, range(-10, 10)))
# result:
[10, 5, 0, 5]
Rough equivalent of implementation:
class iterator:
def map(self, fn):
for v in self:
yield fn(v)
def filter(self, fn):
for v in self:
if fn(v):
yield v
else:
continue
Introduction of such methods will allow to transform collections lazy without
significant memory consumption (as was mentioned in
http://bugs.python.org/issue912738).
----------
components: Interpreter Core, Library (Lib)
messages: 161935
nosy: dair-targ
priority: normal
severity: normal
status: open
title: map() and filter() methods for iterators
type: enhancement
versions: Python 3.4
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue14961>
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