Module 2 · Working with strings · Lesson 1 of 4

Inside a string

You've been writing strings since your very first print. Now look inside one. A string is an ordered sequence of characters, and that means you can reach into it exactly like a list: by index, and by slice.

Same rules as list indexing: word[0] is the first character, word[-1] the last, and word[0:3] is a slice (the stop is excluded). len() counts the characters.

One crucial difference from a list, though: a string is immutable. You can read any part of it, but you can't change a character in place — trying to is a TypeError. Instead, you build a new string, which is exactly what the methods in the next lesson do.