string.replace() question

[Terry Hancock]

Per Jensen wrote:

> The Python doc on string.replace says this:
> 
> replace(str, old, new[, maxsplit])
> """Return a copy of string str with all occurrences of substring old
> replaced by new. If the optional argument maxsplit is given,
> the first maxsplit occurrences are replaced."""
> 
> I must have a blind spot, but the method doesn't seem to work quite like
> that. Example:
> 
> bash-2.05$ python
> Python 2.2.1 (#1, Sep 24 2002, 21:50:51)
> [GCC 2.95.3 20010315 (SuSE)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import string
>>>> string.replace("C:\py21\gallery\resized", "\\", "/")
> 'C:/py21/gallery\resized'
>>>>
> 
> Notice that the last "\" is not replaced with a "/"
> 
> My question is why ?

See if this exercise makes any lights come on:

>>> s = "C:\py21\gallery\resized"
>>> print s 
esized1\gallery

>>> s = r"C:\py21\gallery\resized"
>>> print s
C:\py21\gallery\resized
>>> s
'C:\\py21\\gallery\\resized'

>>> string.replace(s, "\\", "/")
'C:/py21/gallery/resized'

The problem is that the string you are operating on is not the one you 
think it is. "\r" is a carriage return control character, not "\\" + "r" .

Cheers,
Terry

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