Remove specific characters from a Python string

This post will discuss how to remove specific characters from a string in Python.

Since strings are immutable in Python, you cannot simply remove characters from it. However, you can create a copy of a string without specific characters. This post provides an overview of several functions to accomplish this.

1. Using `str.translate()` function

An efficient solution is to use the str.translate() function to remove certain characters from a string. It maps each character of the string through a translation table, which can be created using the str.maketrans() function.

if __name__ == '__main__':

s = 'Hello, World!!'

chars = '.,!'

res = s.translate(str.maketrans('', '', chars))

print(res) # Hello World

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If you have a list of characters, you can use the following code:

if __name__ == '__main__':

s = 'Hello, World!!'

chars = ['.', ',', '!']

res = s.translate(str.maketrans('', '', ''.join(chars)))

print(res) # Hello World

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You can also specify a dictionary to str.maketrans() function. Following is a simple example demonstrating the mapping variant of str.translate():

if __name__ == '__main__':

s = 'Hello, World!!'

chars = ['.', ',', '!']

res = s.translate(str.maketrans({ord(x): '' for x in chars}))

print(res) # Hello World

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2. Using Set

Another option is to filter the string to remove characters that match with the given list of characters.

if __name__ == '__main__':

s = 'Hello, World!!'

removed_chars = ['.', ',', '!']

chars = set(removed_chars)

res = ''.join(filter(lambda x: x not in chars, s))

print(res) # Hello World

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Here’s a generator version of the above code:

if __name__ == '__main__':

s = 'Hello, World!!'

removed_chars = ['.', ',', '!']

chars = set(removed_chars)

res = ''.join(c for c in s if c not in chars)

print(res) # Hello World

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3. Using Regex

Another plausible way is to use regular expressions for removing certain characters from a string. This can be done using the re.sub() function. All characters enclosed within the square brackets constitute a character class, which will be replaced with the second parameter to re.sub(), i.e., an empty string.

import re

if __name__ == '__main__':

s = 'Hello, World!!'

res = re.sub('[.,!]', '', s)

print(res) # Hello World

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If you want to remove all characters present in a literal string, you can use it below. It uses the re.escape() function to escape characters having a special meaning in a regular expression.

import re

if __name__ == '__main__':

s = 'Hello, World!!'

removed_chars = '.,!'

chars = '[%s]+' % re.escape(removed_chars)

res = re.sub(chars, '', s)

print(res) # Hello World

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If you have a list of characters that need to be removed from the string, you can do like:

import re

if __name__ == '__main__':

s = 'Hello, World!!'

removed_chars = '.', ',', '!'

chars = '|'.join(map(re.escape, removed_chars))

res = re.sub(chars, '', s)

print(res) # Hello World

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That’s all about removing specific characters from a string in Python.

Also See:

Remove non-alphanumeric characters from a Python string

Remove specific characters from a Python string

1. Using str.translate() function

2. Using Set

3. Using Regex

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1. Using `str.translate()` function