New String Functions in Python 3.9

Python released its latest major release – Python 3.9.0 on October 5th, 2020. The release comes with a number of new features and optimizations including some new string functions. Also, this is the first version of python to default to the 64-bit installer on Windows.

The new release includes a couple of additional string functions removeprefix() and removesuffix() to remove prefix and suffix from a string respectively. Let’s look at the syntax and usage of the two functions through some examples –

Python String removeprefix()

The following is the syntax for using the removeprefix() function:

s.removeprefix(prefix)

Here, s is the string you want to remove the prefix from. If the string starts with the prefix, it essentially returns s[len(prefix):]. If the string does not start with the prefix, the original string is returned. See the example below:

# remove prefix from a string
print('TicTacToe'.removeprefix('Tic'))
print('TicTacToe'.removeprefix('Tac'))

Output:

TacToe
TicTacToe

In the above example, since 'TicTacToe' starts with the prefix 'Tic', the prefix is removed in the string returned by the removeprefix() function. Whereas, 'TicTacToe' does not start with the prefix 'Tac' hence removeprefix() returns the string as-is.

For more on the function, refer to its official documentation.

Python String removesuffix()

The following is the syntax for using the removesuffix() function:

s.removesuffix(suffix)

Here, s is the string you want to remove the suffix from. If the string ends with the suffix, it essentially returns s[:-len(suffix)]. If the string does not end with the suffix, the original string is returned. See the example below:

# remove prefix from a string
print('TicTacToe'.removesuffix('Toe'))
print('TicTacToe'.removesuffix('Tac'))

Output:

TicTac
TicTacToe

In the above example, since 'TicTacToe' ends with the suffix 'Toe', the suffix is removed in the string returned by the removesuffix() function. Whereas, 'TicTacToe' does not end with the suffix 'Tac' hence removesuffix() returns the string as-is.

For more on the function, refer to its official documentation.

There are also a number of other features and optimizations that have come with this release. Refer to this documentation on what’s new in Python 3.9