[New-bugs-announce] [issue40641] Reserved word pair used in lambda tutorial without being noted as a reserved word

[Chas Belov]

New submission from Chas Belov <docorbit at sonic.net>:

In the tutorial for lambda expressions at https://docs.python.org/3.7/tutorial/controlflow.html#lambda-expressions the reserved word pair is introduced without noting that it is a reserved word. In the example given, I wasn't sure whether pair was a reserved word or whether the interpreter was parsing the plural "pairs" which is presumable an arbitrary name.

Actual content:

The above example uses a lambda expression to return a function. Another use is to pass a small function as an argument:

>>> pairs = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]
>>> pairs.sort(key=lambda pair: pair[1])
>>> pairs
[(4, 'four'), (1, 'one'), (3, 'three'), (2, 'two')]

Candidate expected content:

The above example uses a lambda expression to return a function. Another use is to pass a small function as an argument, for example, the reserved word pair to designate the position in a tuple pair:

>>> items = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]
>>> items.sort(key=lambda pair: pair[1])
>>> items
[(4, 'four'), (1, 'one'), (3, 'three'), (2, 'two')]

----------
assignee: docs at python
components: Documentation
messages: 369017
nosy: docorbit at sonic.net, docs at python
priority: normal
severity: normal
status: open
title: Reserved word pair used in lambda tutorial without being noted as a reserved word
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40641>
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