7.2. Getting the length of a string using len()¶

len() is a built-in function that returns the number of characters in a string:

To get the last letter of a string, you might be tempted to try something like this:

The reason for the IndexError is that there is no letter in “banana” with the index 6. Since we started counting at zero, the six letters are numbered 0 to 5. To get the last character, you have to subtract 1 from length:

Alternatively, you can use negative indices, which count backward from the end of the string. The expression fruit[-1] yields the last letter, fruit[-2] yields the second to last, and so on.