查找子字符串并替换它们但获取它们的信息 [python]

Question

I want to do something like this to a text (This is just an example to show the problem):

new_text = re.sub(r'\[(?P<index>[0-9]+)\]',
            '(Found pattern the ' + index + ' time', text)

Where text is my original text. I want to find any substring like this: [3] or [454] . But this isn't the hard part. The hard part is to get the number in there. I want to use the number to use a method called add_link(number) which expects a number(instead of the string I'm building with "Found pattern..." - that's just an example). (In a database it has stored links matched to IDs where it finds the links.)

Python tells me it doesn't know the local variable index . How can I make it knowing?

Edit: I have been told I didn't ask clearly. (I already have an answer but maybe someone is going to read this in future.) The question was how to get the pattern known as [0-9]+ get as a local variable. I guessed it would be something like this: (?P<index>[0-9]+) , and it was.

Thanx in advanced, Asqiir

Answer 1

You can reference a named group in the replacement string with the syntax \\g<field name> . So your code should be written as:

new_text = re.sub(r'\[(?P<index>[0-9]+)\]', '(Found pattern the \g<index> time', text)