Question

I’m a Python beginner.
I’d like to find <(.+?)> from a string, and replace it with [\1].
For example,

string_input = '<age>'
string_output = '[age]'

I tried,

import re
string = '<age>'
re.sub('<.+?>, '[' + \1 + ']', string)

But it failed.

Answer 1

>>> re.sub('<(.+)>', '[\\1]', '<age>')
'[age]'

Double \\ is used to escaping the \, or else \1 will be recognised as \x01.
Brackets () are used as a capturing group.

You can use multiple capturing groups like this:

>>> re.sub('<(.+)=+(.*)>', '[\\1: \\2]', '<age=5>')
'[age: 5]'