Why is the output: match 1. match 2

Question

import re
pattern = r"(.+) \1"
match = re.match(pattern, "word word")
if match:
print ("Match 1")
match = re.match(pattern, "?! ?!")
if match:
print ("Match 2")
match = re.match(pattern, "abc cde")
if match:
print ("Match 3")

Answer 1

\1 means the thing that appeared in the first parentheses. The first parentheses included .+, which matches anything. So the regular expression is essentially something, space, that something again. “word word” and “?! ?!” both match that pattern.