multiprocessing.Pool is missing a starmap[_async]() method.

[hynek]

BPO	12708
Nosy	@amauryfa, @pitrou, @hynek
Files	c02fbcda56f3.diff: Patch to add starmap() and starmap_async() in multiprocessing + tests + docs.

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2011-12-21.10:05:02.656>
created_at = <Date 2011-08-08.08:21:45.954>
labels = ['type-feature', 'library']
title = 'multiprocessing.Pool is missing a starmap[_async]() method.'
updated_at = <Date 2011-12-21.10:05:02.654>
user = 'https://github.com/hynek'

bugs.python.org fields:

activity = <Date 2011-12-21.10:05:02.654>
actor = 'pitrou'
assignee = 'none'
closed = True
closed_date = <Date 2011-12-21.10:05:02.656>
closer = 'pitrou'
components = ['Library (Lib)']
creation = <Date 2011-08-08.08:21:45.954>
creator = 'hynek'
dependencies = []
files = ['24063']
hgrepos = ['97']
issue_num = 12708
keywords = ['patch']
message_count = 11.0
messages = ['141761', '141768', '141935', '141941', '149914', '149916', '149921', '149922', '149923', '149975', '149976']
nosy_count = 6.0
nosy_names = ['amaury.forgeotdarc', 'pitrou', 'jnoller', 'neologix', 'python-dev', 'hynek']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue12708'
versions = ['Python 3.3']

[hynek]

After I've seen a co-worker to unpack tuples while using multiprocessing.Pool.map(), I realized that the module is missing a starmap() method like itertools has.

I took it as a opportunity to contribute some code and implemented both starmap() and starmap_async().

The patch including tests is attached, please let me know, what you think. Please don't call me names, it's my first patch for such a high profile project like Python. ;)

[hynek]

In all my excitement, I somehow presumed that the docstring automagically lands in the docs. Added doc entries to patch (I hope they aren't too crude, I'm not a native speaker).

Same as first patch otherwise.

[amauryfa]

+def starmapstar(args):
+ return list(itertools.starmap(args[0], args[1]))

Is your new function restricted to 2 arguments?

[hynek]

No, that's just a helper function like the mapstar directly above. args[1] is the iterable with tuples that get unpacked as arguments.

[pitrou]

This looks like a reasonable request to me, and the patch looks generally ok as well.

[pitrou]

One nit: the patch needs "versionadded" tags for the two new functions.

[hynek]

Thanks for the feedback Antoine!

I updated the patch to latest default tip and added the requested tags to the docs.

[neologix]

Looks good to me, except for another minor nit:
"""
the elements of the iterable are expected to be tuples
"""

AFAICT, you just require the elements of ìterables to be iterables, not necessarily tuples.

[hynek]

You're right. I've updated the docs accordingly, thanks!

[python-dev]

New changeset b07b1e58582d by Antoine Pitrou in branch 'default':
Issue bpo-12708: Add starmap() and starmap_async() methods (similar to itertools.starmap()) to multiprocessing.Pool.
http://hg.python.org/cpython/rev/b07b1e58582d

[pitrou]

Patch committed. Thanks for your contribution!