Regular expressions in Python: Replace starting and closing brackets with dynamic/incremental string-CodePudding

I have a string that holds sub-strings enclosed in starting and closing brackets. For example:

"We want to visit that place (HBD) and meet our friends (DTO) after a long time. We really love having such gatherings at this time of year (XYZ). Let's do it."

I want to replace each pair of starting and closing brackets with a string containing a number that is increasing after every encounter of pair of brackets. Like it should be:

"We want to visit that place sb1-HBD-eb1 and meet our friends sb2-DTO-eb2 after a long time. We really love having such gatherings at this time of year sb3-XYZ-eb3. Let's do it."

If anyone can help me to provide some regular expression way to solve this problem. Thank you.

CodePudding user response：

One approach, it to take advantage of the fact that re.sub can take a function as the repl argument and create a function that will remember how many times it has matched before:

import re
from itertools import count

s = "We want to visit that place (HBD) and meet our friends (DTO) after a long time. We really love having such gatherings at this time of year (XYZ). Let's do it."


def repl(match, counter=count(1)):
    val = next(counter)
    return f"sb{val}-{match.group(1)}-eb{val}"


res = re.sub("\((.*?)\)", repl, s)
print(res)

Output

We want to visit that place sb1-HBD-eb1 and meet our friends sb2-DTO-eb2 after a long time. We really love having such gatherings at this time of year sb3-XYZ-eb3. Let's do it.

The pattern "\((.*?)\)" will match anything inside parenthesis, you can find a better explanation for a similar pattern in the Greedy versus Non-Greedy section of the Regular Expression HOWTO.