Remove special characters from a string except space in Python

This tutorial is about removing the special characters in a string where we need to remove all the special characters except for a space in the string. This is a very interesting task to do and will also be proved to be helpful. I had been asked this question in one of my placement drives.

Example- There is a string consisting of the following sentences- “Hello! We% are %#$%^ trying ^&%$to remove^& special! characters%^ from*( a(^ string": except{} for_a space.”

So the corresponding output after removing special characters is-“Hello We are trying to remove special characters from a string except for a space.”

This could be done using a tool in Python known as Regex.

A regex is a tool that is a shorthand for Regular expression. We can do many tasks like checking for a specified pattern in a string.

Python has a built-in module known as re which is imported with a lot of functions like findall(), search(), split() etc.

Removing special characters from a string except space

We will implement this using two ways-

1. Using findall()
2. Using sub()

Method 1: Using findall()

We are going to use findall() function which finds a pattern then replaces the pattern and returns the string.

Here is the implementation of Regex as-

import re
string = '''Hello! We% are %#$%^ trying ^&%$to remove^& special! characters%^ from*( a(^ string": except{} for_a space.'''

for a in string.split("\n"):
    string1 = " ".join(re.findall(r"[a-zA-Z0-9]+", a))
    print(string1)

Output:

Hello We are trying to remove special characters from a string except for a space

In line 1, we have imported the regular expression library as re.

The string is defined with some special characters which need to be removed. A for loop is used white iterates in string and then finds all the a-z, A-Z,0-9 and replaces it with itself and does not encounter character except this.

At last, the string is printed.

Method 2: Using sub()

The next implementation of this problem can be solved using a different approach that implements sub().

sub() handles the regular expression by substituting which replaces the string after the replacement of matched pattern and returns it.

import re
string = '''Hello! We% are %#$%^ trying ^&%$to remove^& special! characters%^ from*( a(^ string": except{} for_a space.'''

for a in string.split("\n"):
    print(re.sub(r"[^a-zA-Z0-9]+", ' ', a))

Output:

Hello We are trying to remove special characters from a string except for a space

Here it substitutes all the other letters, digits, and alphabets into a space.

Here in this task, we have discussed two methods to remove special characters from any string. I hope you found this helpful. Also, you can visit official documentation for various metacharacters in regex.

One response to “Remove special characters from a string except space in Python”

1. ddd says:

   December 8, 2022 at 7:44 pm

   import re
   string = ”’Hello! We% are %#$%^ trying ^&%$to remove^& special! characters%^ from*( a(^ string”: except{} for_a space.”’

   for a in string.split(“\n”):
   print(re.sub(r”[^a-zA-Z0-9]+”, ‘ ‘, a))

   Reply