Problem with regular expression

Tim Chase python.list at tim.thechases.com
Sun Mar 7 14:35:31 CET 2010


Joan Miller wrote:
> I would to convert the first string to upper case. But this regular
> expression is not matching the first string between quotes.
> 
>   re.sub("'(?P<id>\w+)': [^{]", "\g<id>FOO", str)

Well, my first thought is that you're not using raw strings, so 
you're not using the regexps and replacements you think you are.

   r"'(?P<id>\w+)': [^{]"

will match the lines of interest.  The replacement will eat the 
opening & closing single-quote, colon, and first character.

> # string to non-matching
> 'foo': {
> 
> # strings to matching
> 'bar': 'bar2'
> 'bar': None
> 'bar': 0
> 'bar': True
> 
> So, i.e., from the first string I would to get:
>   'BAR': 'bar2'

I think you'd have to use a function/lambda to do the 
case-conversion:

   re.sub(
     r"'(?P<id>\w+)(?=': [^{])",
     lambda m: "'" + m.group('id').upper(),
     string_of_interest
     )

Or you could just forgo regexps and use regular string functions 
like split(), startswith(), and upper()

-tkc







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