python call external program (WHAT THE?!)

[Berthold Hoellmann]

Ben Thomas wrote:
> 
> Hey guys the below is true with the addition of
> system('d:\\data\\vacman\\mybat.bat') = ok
> 
> Have I found a bug? Do I get a t-shirt? :) Could a py-xpert explain to me my
> results?
> 
> Ben

>python

Not a bug, a feature. The backslash has special meaning in python
strings:

Python 1.5.2 (#2, Jul  7 1999, 09:18:40) [C] on sunos5
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> print '\d'
\d
>>> print '\b'
 
>>> print '\m'
\m
>>> print 'ab\bcd'
acd
>>> 

\b seems to be interpreted a backspace character, deleting the last
character. This is avoided by doubeling the backslash, or using
r(aw/egexp) strings, i.e. system(r'd:\data\vacman\mybat.bat'), but be
carefull, os.listdir (r'd:\data\vacman\') won't give, what you expect.

Cheers

Berthold
-- 
email: hoel at GermanLloyd.org
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C[_]  These opinions might be mine, but never those of my employer.