How to remove all the special characters from a text file in Python

In this blog, we will be seeing how we can remove all the special and unwanted characters (including whitespaces) from a text file in Python. first of all, there are multiple ways to do it, such as Regex or inbuilt string functions; since regex will consume more time, we will solve our purpose using inbuilt string functions such as isalnum() that checks whether all characters of a given string are alphanumeric or not.

We will also require some basic file handling using Python to fulfil our goal.

Opening and reading a text file:

We can open a .txt file by using the open() function and read the contents line by line.

Myfile = open("input.txt", "r")
#my text is named input.txt
#'r' along with file name depicts that we want to read it

Checking all characters of the text file:

It will check all characters for any special characters or whitespaces. We use the function isalnum() and remove all the non-alphanumeric characters and display the content of the text file. The complete code shall look like:

Myfile = open("input.txt", "r")

#my text is named input.txt 
#'r' along with file name depicts that we want to read it

for x in Myfile:
    a_string = x;

    alphanumeric = " "

    for character in a_string:
        if character.isalnum():
            alphanumeric += character
    print(alphanumeric)

Contents of the input.txt are shown below:

This is demo For checking ]][/';;'.%^ these chars @%^* to be removed $ ^ %   %..;
i am not @^$^(*&happy%$%@$% about %%#$%@ coro%%na virus 19
i #@love**&^ codespeedy%^().

The output will look like this:

 ThisisdemoForcheckingthesecharstoberemoved
 iamnothappyaboutcoronavirus19
 ilovecodespeedy

We can clearly see that the whitespaces and special characters have been eliminated successfully.

Also read: Replace comma with a new line in a text file using Python