Question

Suppose I have this string:
s = "blah blah blah"

Using Python regex, how can I replace each instance of “blah” with a different value (e.g. I have a list of values v = ("1", "2", "3")

Answer 1

You could use a re.sub callback:

import re
def callback(match):
    return next(callback.v)
callback.v=iter(('1','2','3'))

s = "blah blah blah"
print(re.sub(r'blah',callback,s))

yields

1 2 3