Question

I am trying to replace a variable stored in another file using regular expression. The code I have tried is:

r = re.compile(r"self\.uid\s*=\s*('\w{12})'")
for line in fileinput.input(['file.py'], inplace=True): 
    print line.replace(r.match(line), sys.argv[1]), 

The format of the variable in the file is:

self.uid = '027FC8EBC2D1'

I am trying to pass in a parameter in this format and use regular expression to verify that the sys.argv[1] is correct format and to find the variable stored in this file and replace it with the new variable.

Can anyone help. Thanks for the help.

Answer 1

You can use re.sub which will match the regular expression and do the substitution in one go:

r = re.compile(r"(self\.uid\s*=\s*)'\w{12}'")
for line in fileinput.input(['file.py'], inplace=True):
    print r.sub(r"\1'%s'" %sys.argv[1],line),