[Python: falsey strings and string comparison] #strings #falsey #python

string_comp.py

#!/usr/bin/env python3
# https://github.com/keystroke3/redpaper/issues/1#event-2480042391

def empty_string_checker(s):
    if not s:                                                   # this is equivalent to saying `if s == "":`
        print("String is empty!")
    if s:                                                       # this is equivalent to saying `if s != "":`
        print("String is not empty -- it contains '{}'".format(s))

g = ""
empty_string_checker(g)                                         # --> String is empty!
f = "hiya there"
empty_string_checker(f)                                         # --> String is not empty -- it contains 'hiya there'

def string_compare(s):
    if s != "hi" or s != "Hi" or s != "HI" or s != "hI":        # this is equivalent to saying `if not s.lower():`
        print("String does not equal 'hi' in any upper or lower case combination")
    if s.lower() == "hi":                                       # instead of checking all the possible case combinations of "hi" we can just check if the lowercase instance (or uppercase) of the variable is equal to the lowercase string we want
        print("String does equal 'hi' and we only had to do one check! -- string: '{}'".format(s))

p = "hello"
string_compare(p)                                               # --> String does not equal 'hi' in any upper or lower case
j = "hI"
string_compare(j)                                               # --> String does equal 'hi' and we only had to do one check! -- string: 'hI'