Remove Punctuation From String Python

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How to remove punctuation from the string in Python? You can remove punctuation from a string using the string module and some string manipulation techniques. This step is often necessary when dealing with Natural Language Processing (NLP) tasks, as it allows you to focus on the raw content of the text without any unnecessary special characters that don’t contribute to its meaning.

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You can remove punctuation from the string in Python using many ways, for example, by using translate(), replace(), re.sub(), filter(), join() and for loop, punctuation string, and not in operator. In this article, I will explain how to remove punctuation from the string by using all these functions with examples.

1. Quick Examples of Removing Punctuation From String

If you are in a hurry, below are some quick examples of removing punctuation from a string.


# Quick examples of removing punctuation From string

import string
import re

# Initialize the string
my_string = "^(!Welcome; @#T%o: &*SparkByExamples()!"

# Example 1: Using the string.translate() method
# Remove punctuation from a string 
result = my_string.translate(str.maketrans('', '', string.punctuation))

# Example 2: Using replace() method
# Remove punctuation from a string 
for punctuation in string.punctuation:
    my_string = my_string.replace(punctuation, '')

# Example 3: Using re.sub() method
# Remove punctuation from the string
my_string = re.sub(r'[^\w\s]', '', my_string)

# Example 4: Using filter() function to remove punctuation
filtered_chars = filter(lambda x: x.isalnum() or x.isspace(), my_string)
my_string = ''.join(filtered_chars)

# Example 5: Using for loop to remove punctuation
punctuation_chars = '''!()-[]{};:'"\,<>./?@#$%^&*_~'''
new_string = ''
for char in my_string:
    if char not in punctuation_chars:
        new_string += char

# Example 6: Using for loop, punctuation string, and not in operator
punctuation_chars = string.punctuation 
new_string = ''
for char in my_string:
    if char not in punctuation_chars:
        new_string += char

# Example 7: Using join() method
# Remove punctuation from the string
new_string = ''.join(char for char in my_string if char not in punctuation_chars)

# Example 8: Using join() method to remove punctuation
punctuation_chars = set(string.punctuation)
new_string = ''.join(char for char in my_string if char not in punctuation_chars)

2. Remove Punctuation from a String Using the string.translate() Method

You can remove punctuation from the string using the string.translate() method. For example, first import the string module which provides a string containing all ASCII punctuation characters. You can initialize the string including some punctuations named my_string , and apply the str.translate() method to it. str.maketrans() is a function of a string module that allows you to efficiently remove specific characters or groups of characters from a string.


import string

# Initialize string
my_string = "^(!Welcome; @#T%o: &*SparkByExamples()!"
print("Original string:", my_string)

# Using the string.translate() method
# Remove punctuation from a string 
result = my_string.translate(str.maketrans('', '', string.punctuation))
print("After removing punctuation from the string:", result)

Yields below output.

python remove punctuation string

As you can see, all punctuation characters, such as ^, (, !, ;, @, #, %, :, &, *, and (), have been removed from the original string, leaving only the alphanumeric characters intact.

3. Python Replace Punctuations with Space

You can remove punctuation from a string using the str.replace() method. For example, first import the string module which provides a string containing all ASCII punctuation characters. Initializing a string my_string with a mix of alphanumeric and punctuation characters. Using a for loop to iterate over each punctuation character present in the string.punctuation. Inside the loop, use the replace() method to remove each punctuation character from the my_string.


import string

# Initialize string
my_string = "^(!Welcome; @#T%o: &*SparkByExamples()!"
print("Original string:", my_string)

# Using replace() method
# Remove punctuation from a string 
for punctuation in string.punctuation:
    my_string = my_string.replace(punctuation, ' ')
print("After removing punctuation from the string:", my_string)

# Output:
# Original string: ^(!Welcome; @#T%o: &*SparkByExamples()!
After removing punctuation from the string:    Welcome    T o    SparkByExamples

4. Remove Punctuation from a String Using re.sub() Method

You can also use the re.sub() method from the re module in Python to remove punctuation from a string. This method allows you to replace patterns (in this case, punctuation characters) with a specified replacement (in this case, an empty string ”).

In the below example, you can use the regular expression [^\w\s] in the re.sub() method. \w: Matches any alphanumeric character (word character). \s: Matches any whitespace character. [^\w\s]: This pattern matches any character that is not alphanumeric or whitespace. By replacing all such characters with an empty string, you effectively remove all punctuation from the string.


import re

# Initialize string
my_string = "^(!Welcome; @#T%o: &*SparkByExamples()!"
print("Original string:", my_string)

# Using re.sub() method
# Remove punctuation from the string
my_string = re.sub(r'[^\w\s]', '', my_string)
print("After removing punctuation from the string:", my_string)

# Output:
# Original string: ^(!Welcome; @#T%o: &*SparkByExamples()!
# After removing punctuation from the string: Welcome To SparkByExamples

5. Using the filter() Function

You can also use the filter() function with str.isalnum() to remove punctuation from a string. The filter() function filters elements of an iterable based on a given function. In this case, you can use str.isalnum() to keep only the alphanumeric characters in the string and remove the punctuation.

In the below example, filter() is used to keep only the characters that satisfy the condition specified in the lambda function. The lambda function lambda x: x.isalnum() or x.isspace() checks if the character x is alphanumeric or a whitespace character. If it is, it is kept in the filtered_chars list. Finally, you join the characters in the filtered_chars list to create the new string with punctuation removed.


# Initialize string
my_string = "^(!Welcome; @#T%o: &*SparkByExamples()!"
print("Original string:", my_string)

# Using filter() function to remove punctuation
filtered_chars = filter(lambda x: x.isalnum() or x.isspace(), my_string)
my_string = ''.join(filtered_chars)
print("After removing punctuation from the string:", my_string)

Yields the same output as above.

6. Using For Loop, Punctuation String, and not in Operator

You can remove punctuation from a string using a for loop, a punctuation string, and the not in operator to check if a character is not a punctuation character.

In the below example, you can use the string.punctuation string, which contains all the punctuation characters. Then iterate through each character my_string, and if the character is not present in the punctuation_chars string, you can add it to the new_string. This way, you build the new string with punctuation removed.


import string

# Initialize string
my_string = "^(!Welcome; @#T%o: &*SparkByExamples()!"
print("Original string:", my_string)

# Initializing punctuations string
punctuation_chars = '''!()-[]{};:'"\,<>./?@#$%^&*_~'''
# Using for loop to remove punctuation
new_string = ''
for char in my_string:
    if char not in punctuation_chars:
        new_string += char
print("After removing punctuation from the string:", new_string)

# Using for loop, punctuation string, and not in operator
punctuation_chars = string.punctuation 
new_string = ''
for char in my_string:
    if char not in punctuation_chars:
        new_string += char
print("After removing punctuation from the string:", new_string)

Yields the same output as above.

7. Using the join() Method

You can also use the join() method to remove punctuation from a string. For example, you use a generator expression within the join() method. The generator expression (char for char in my_string if char not in punctuation_chars) iterates through each character my_string, and if the character is not present in the punctuation_chars string, it yields the character. The join() method then combines these characters into a single string, effectively removing the punctuation characters.


import string

# Initialize string
my_string = "^(!Welcome; @#T%o: &*SparkByExamples()!"
print("Original string:", my_string)

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

# Using join() method
# Remove punctuation from the string
new_string = ''.join(char for char in my_string if char not in punctuation_chars)
print("After removing punctuation from the string:", new_string)

# Using join() method to remove punctuation
punctuation_chars = set(string.punctuation)
new_string = ''.join(char for char in my_string if char not in punctuation_chars)
print("After removing punctuation from the string:", new_string)

Yields the same output as above.

Conclusion

In this article, I have explained how to remove punctuation from the string in Python by using the translate(), replace(), re.sub(), filter(), join() and for loop, punctuation string, & not in operator with examples.

Happy Learning !!

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