How to Remove Punctuations From a String in Python

In this post, we will learn how to remove punctuation from a string in Python, with a detailed explanation and example.

There are two different ways to remove punctuations in Python:

1. Using for-loop &
2. Using Python functions

But before we jump into the programming part, let’s discuss very basic questions such as what is punctuation and why do we need to remove it from the string.

What is Punctuation?

Punctuation marks are special symbols, such as full stops, commas, question marks, exclamation points, and more, used in writing to separate sentences and clarify meaning.

Some symbols of punctuations are: !"#$%&'()*+,-./:;<=>?@[]^_`{|}~

Why do we need to remove Punctuations from the string?

Removing punctuations from the string is a very common task when preparing datasets for any text classifier in machine learning, and it is also essential when dealing with NLP (Natural Language Processing) related tasks. This process helps improve model performance.

That’s why it’s important to know how to remove punctuation from the string, and it’s also very simple. Now that we know all the basic things, let’s jump into the programming part.

Remove Punctuations From a String in Python Using for-loop

Let’s start with the algorithm first and understand each step of how to write this program. After that, we can move on to the coding part and see the output.

Algorithm

1. Ask the user to enter their sentence and store it in a variable called sentence.
2. Create one variable called punctuations and store each punctuation in string format (punctuations = "!\"#$%&'()*+,-./:;<=>?@[\]^_`{|}~").
3. Create a variable called new_string for storing sentences without punctuations initially it is empty.
4. Iterate in a sentence using for-loop and inside for-loop check:
   if i not in punctuations then do new_string +=i
5. At the end, outside of the for-loop print new_string.

Few prerequisites for this program:
How to take input from the user
For-loop
Python Strings

Source Code

sentence = input("Please enter your sentence: ")

punctuations = "!\"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"

new_string = ''

for i in sentence:
    if i not in punctuations:
        new_string +=i

print(new_string)

Output

Please enter your sentence: Hello! how are you? am fine...
Hello how are you am fine

Now let’s modify this program and write it using Python functions and list comprehension.

Remove Punctuations From a String in Python Using Function

Few prerequisites for this program:
How to take input from the user
Python Strings & String methods (join())
Python Functions
List comprehension
Python built-in string module.

Source Code

import string

# define a function
def remove_punctuation(text):
    return ''.join(char for char in text if char not in string.punctuation)

# user input
sentence = input("Please enter your sentence: ")

# call a function
print(remove_punctuation(sentence))

Output

Please enter your sentence: Hello! how are you? let's start learning Python.
Hello how are you lets start learning Python

This is all about how to remove punctuation from a string in Python. I hope this post adds some value to your life thank you for reading.