How do I verify that a string only contains letters, numbers, underscores and dashes?

Question

I know how to do this if I iterate through all of the characters in the string but I am looking for a more elegant method.

Answer 1

As an alternative to using regex you could do it in Sets:

from sets import Set

allowed_chars = Set('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-')

if Set(my_little_sting).issubset(allowed_chars):
    # your action
    print True