Destroy 2 caracters after a number

I need help, in a long string, I want to know the the 2 characters after a number

example = "gz15gr123da1az4gr1sd23f168zgre4r6z"
if in example after 1 number == "gr":
so delete "gr"

>Solution :

If I understand your question correctly, what you need is regex:

import re
example = "gz15gr123da1az4gr1sd23f168zgre4r6z"
re.sub("(\d)gr", r"\1", example)

Output

gz15123da1az41sd23f168zgre4r6z

Explnatation

The re.sub function takes three arguments: the first argument is a patter, the second one the replacement, and the last of is the string itself. (\d)gr selects the parts that contain a number followed by gr, then replaces it with the number (\d) itself(removing the gr part).