math.prod can return integers (contradicts doc)

[outofmbufs]

BPO	46828
Nosy	@rhettinger, @outofmbufs

^{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 = 'https://github.com/rhettinger'
closed_at = None
created_at = <Date 2022-02-22.19:04:33.966>
labels = ['type-bug', 'docs']
title = 'math.prod can return integers (contradicts doc)'
updated_at = <Date 2022-02-23.01:41:08.483>
user = 'https://github.com/outofmbufs'

bugs.python.org fields:

activity = <Date 2022-02-23.01:41:08.483>
actor = 'rhettinger'
assignee = 'rhettinger'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2022-02-22.19:04:33.966>
creator = 'neilwebber'
dependencies = []
files = []
hgrepos = []
issue_num = 46828
keywords = []
message_count = 2.0
messages = ['413741', '413763']
nosy_count = 3.0
nosy_names = ['rhettinger', 'docs@python', 'neilwebber']
pr_nums = []
priority = 'low'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue46828'
versions = []

Linked PRs

• gh-90984: clarify math.rst preamble sentence about return types #124297

[outofmbufs]

The math module documentation says:

Except when explicitly noted otherwise, all return values are floats.

But this code returns an integer:

   from math import prod; prod((1,2,3))

Doc should "explicitly note otherwise" here, I imagine. The issue being wanting to know that the result on all-integer input will be an exact (integer) value not a floating value.

[rhettinger]

I'll add a note that the output type is determined by the input type.

[ChanceCarmichael]

I would like to try working this issue. Is it still available? It would be my first ever contribution to Python.

[skirpichev]

@rhettinger, I think that the prod docs does "explicitly notes": "Calculate the product of all the elements in the input iterable." - and there is no doubts about the output type. Other cases (e.g. math.perm) are also very clear as exceptions.