Did I miss something? Can someone explain how this worked?

Question

Don't remember learning about 'x. strip()'
https://code.sololearn.com/cWbKD0TAW6tm/?ref=app

Answer 1

lines in file are:

Harry Potter
The Hunger Games
Pride and Prejudice
Gone with the Wind

num is List of this lines
for each line in list it prints:
first character + length of line,
but without spaces and \n at the end
(it's rstrip() job)

H12
T16
P19
G18