How can I convert fstring to str.format?

Question

HEADER_LENGTH = 10
my_username = input("Username: ")
username = my_username.encode()
username_header = f"{len(username):<{HEADER_LENGTH}}"

How can I 'username_header' be changed from fstring to str.format()? I must run on python3.5. so I can't use fstring.

Answer 1

This must work:

username_header = '{0:<{1}}'.format(len(username),HEADER_LENGTH)

you can use keyword args also

 username_header = '{user_len:<{header_len}}'.format(user_len=len(username),header_len=HEADER_LENGTH)