[docs] [issue28197] range.index mismatch with documentation

Sept. 18, 2016

      New submission from Vedran Čačić:

Look at this:

    >>> from collections.abc import Sequence

    >>> help(Sequence.index)
    index(self, value, start=0, stop=None)
        S.index(value, [start, [stop]]) -> integer -- return first index of value.
        Raises ValueError if the value is not present.

    >>> issubclass(range, Sequence)
    True

    >>> help(range.index)
    index(...)
        rangeobject.index(value, [start, [stop]]) -> integer -- return index of value.
        Raise ValueError if the value is not present.

So far, so good. But:

    >>> range(9).index(2, 1, 5)
    TypeError: index() takes exactly one argument (3 given)

Of course it's not essential, but the docs shouldn't lie. And if range _is_ a Sequence, then it should have the complete interface of a Sequence. Including start and end arguments for .index: they are optional from the point of call, not from the point of implementation. :-)

----------
assignee: docs@python
components: Documentation, Library (Lib)
messages: 276908
nosy: docs@python, veky
priority: normal
severity: normal
status: open
title: range.index mismatch with documentation
type: behavior
versions: Python 3.5, Python 3.6

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Python tracker <report@bugs.python.org>
<http://bugs.python.org/issue28197>
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