String Length in Python

We can get the length of a string using the len() function like this:

message = "Hello world"

# Printing the length:
print(len(message)) # Output: 11

# Changing the message:
message += "!"

# Printing the new length:
print(len(message)) # Output: 12

Accessing characters from the end:

The length is useful for accessing characters from the end of a string.

Because strings are 0-indexed, the index of the last character is length - 1:

message = "Hello world"
length = len(message)

# Printing the last character:
print(message[length - 1]) # Output: d

# Printing the second to last character:
print(message[length - 2]) # Output: l

In general, if you want the nth last character, you access message[length - n].

Slicing characters from the end:

The length is also useful for slicing some characters from the end of a string:

message = "Hello world"
length = len(message)

# Slicing last 4 characters:
lastChars = message[length - 4:]
print(lastChars) # Output: orld

# Slicing last 7 characters:
lastChars = message[length - 7:]
print(lastChars) # Output: o world

In general, if you want to slice the last n characters, you use message[length - n:].

Assignment
Follow the Coding Tutorial and let's practice with string length!

Hint
Look at the examples above if you get stuck.