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From: Mel <mwilson@the-wire.com>
Newsgroups: comp.lang.python
Subject: Re: bug in str.startswith() and str.endswith()
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Date: Fri, 27 May 2011 09:03:55 -0400
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Terry Reedy wrote:

> To me, that says pretty clearly that start and end have to be
> 'positions', ie, ints or other index types. So I would say that the
> error message is a bug. I see so reason why one would want to use None
> rather that 0 for start or None rather than nothing for end.

If you're trying to wrap a call to startswith in a function that "looks 
like" startswith, there's no easy way to pass in the information that your 
caller wants the default parameters.  The case I ran into was

def wrapped_range (start, stop=None, span=None):
    do_some_things()
    result = range (start, stop, span)	# range doesn't(/didn't) accept this
    return result
   

Tne answer in that case was to take *args as the parameter to wrapped_range 
and count arguments to distinguish between the different calls to range. 

	Mel.