About Python MCQ

Question

import re
str = 'sololearn123'
print(re.sub(r'[aA-zZ]',",str))

How the output is 123?

Answer 1

Hi, Mustakim Rahman !
re.sub replace whats in the first argument with that in the second argunent. So it takes the substring with all characters aA-zZ an replace it with nothing. Left is the numbers (digits).

# As an example:
import re
str = 'soloLearn123'
print(re.sub(r'[A-Z]', 'Q', str))

# becomes: soloQearn123

# As an second example:
import re
str = 'soloLearn123'
print(re.sub(r'[a-z]', '', str))

# becomes: L123