A string can be thought of as a list of characters.

Like any other list, each character in a string has an index. Consider the string:

favorite_fruit = "blueberry"

We can select specific letters from this string using the index. Let’s look at the first letter of the string.

print(favorite_fruit[1])
# Output: l

Whoops, is that the first letter you expected? Notice that the letter at index 1 of "blueberry" isn’t b, it’s l. This is because the indices of a string start at 0. b is located at the zero index and we could select it using:

print(favorite_fruit[0])
# Output: b

It’s important to note that indices of strings must be integers. If we were to try to select a non-integer index we would get a TypeError.

For example:

print(favorite_fruit[1.5])

This would result in:

Traceback (most recent call last):
  File "script.py", line 3, in <module>
    print(favorite_fruit[1.5])
TypeError: string indices must be integers