Replace String with increasing numer [SOLVED]

[AlphaInc]

If it's not too huge, I'd just loop over it. But for very large files, that's inefficient.

paragraph = """This example is an example on how to make an
example with the word example. the example ends here with an example. for example"""

target = "example"
counter = 0
while target in paragraph:
    counter += 1
    paragraph = paragraph.replace(target, str(counter), 1)

print(paragraph)

If it is huge, time to break out regex parser. I think there should be a simpler way to write a callable incrementor, but this will do for now.

import re

target = "example"

def str_counter(match_object):
    str_counter.count += 1
    return str(str_counter.count)
str_counter.count = 0

paragraph = """This example is an example on how to make an
example with the word example. the example ends here with an example. for example"""

paragraph = re.sub(re.escape(target), str_counter, paragraph)

print(paragraph)

Hey, thanks for replying.
Where do I have to define that my script should check in text-files? And what's the difference between target and paragraph?