python - how to replace regular expression based on the match results (e.g. a special function)? -

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i have search expression 1-2 groups.

i need substitute each result depends on result value.

e.g. in following string, replace each matched digit it's value * 3.

s = 'a4cd5cd782cd' reg = '([1-9])cd' def f(x): return str(int(x)*3)

expected result: 

'a12cd15cd786cd'

how can substitute function?

thanks

>>> import re >>> s = 'a4cd5cd782cd' >>> reg = r'([1-9])cd' >>> def f(x): return str(int(x.group(1))*3)+"cd" ... >>> re.sub(reg, f, s) 'a12cd15cd786cd'

read the docs here.


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