[New-bugs-announce] [issue14924] re.finditer() oddity

[Francisco Gracia]

New submission from Francisco Gracia <fgragu023 at gmail.com>:

I find baffling the following behaviour of *re.finditer()*:

    Python 3.2 (r32:88445, Feb 20 2011, 21:29:02) [MSC v.1500 32 bit (Intel)] on win32
    Type "copyright", "credits" or "license()" for more information.
    >>> import re
    >>> m = re.finditer( '123', 'abc' )
    >>> m
    <callable_iterator object at 0x00BF09B0>
    >>> if m : 'I am Napoleon'
    
    'I am Napoleon'

No other way of formulating the condition that I have tried has worked either. Apparently *m* is always true, although all efforts to test its value indicate the contrary:

    >>> m == True
    False
    >>>

This does not happen with any other of the related methods (*findall*, *match*, *search*), which no doubt is the correct and logical behaviour:

    >>> n = re.findall( '123', 'abc' )
    >>> n
    []
    >>> if n : 'I am Napoleon'
    
    >>> 

I have not seen any warning or explanation for this fact in the official or third party documentation that I have consulted. Perhaps it is not a bug, but, as the preceding lines show, it makes impossible to test the result of the operation and direct the subsequent program flow.

If this were an unavoidable feature of *re.finditer*, it should be at least clearly exposed and, if possible, with indications of how to circumvent its undesirable consequences.

Thanks for your attention and efforts.

----------
components: Regular Expressions
messages: 161705
nosy: ezio.melotti, fgracia, mrabarnett
priority: normal
severity: normal
status: open
title: re.finditer() oddity
type: behavior
versions: Python 3.2

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<http://bugs.python.org/issue14924>
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