Newbie question: string replace

[Diez B. Roggisch]

usgog at yahoo.com wrote:
> I have a config file with the following contents:
> service A = {
>   params {
>     dir = "c:\test",
>     username = "test",
>     password = "test"
>   }
> }
> 
> I want to find username and replace the value with another value. I
> don't know what the username value in advance though. How to do it in
> python?

Could be done using regular expressions. Ususally for such tasks one 
would prefer pythons string manipulation functions, but if you want to 
preserve whitespace, I think a rex is in order here:


import re, sys


new_name = "foobar"

rex = re.compile(r'(^.*username *=[^"]*")([^"]*)(".*$)')
for line in sys.stdin:
     m = rex.match(line)
     if m is not None:
         line = "%s%s%s\n" % (m.group(1), new_name, m.group(3))
     sys.stdout.write(line)



use with

python script.py < config_in > config_out

Regards,

Diez