If my_string = "this is my string! ", why does print (my_string[0: 7: 5]) return "ti" and not
"t i"?
much

In Python, a string is an array of characters, we can access these characters using index operator []. For example, we have a_string = "Hello World" a_string[0] prints the first character in string ('H').

We can also use index operator to make substrings, for example a_string[0:3] will make a substring with first, second, third and fourth character equal to "Hell".

Now to business

my_string = "This is MY string!"

print(my_string[0:7]) # Prints "This is "

print(my_string[0:7:5]) # Prints "T" then prints the sixth character since we start counting at 0 hence prints "Ti" (note that space is also a character).

Hope this helps.