Function doesn't remove punctuations

January 22, 2022

I’m new with python and I’m having problems with my function. I need to remove punctuation symbols from the string, so, the simplest thing I could think up is to loop the string and replace the punctuation for an empty character; though the function actually does remove full stops, it doesn’t do it with the comma. I tried to debug it and it recognises the comma in the condition, but it doesn’t remove it.

The code is this:

string = "the Zen of Python, by Tim Peters. beautiful is better than ugly. explicit is better than implicit. simple is better than complex."


def remove_punctuation(string):

    punctuation = [",", "."]

    for char in string:
        if char in punctuation:
            raw_string = string.replace(char, "")

    return raw_string

print(remove_punctuation(string))

The thing is the exercise says I can only use replace or del, so I’m a bit restricted with this.

>Solution :

solution number 1:

with replacing:

def remove_punctuation(string):
    punctuation = [",", "."]

    for char in punctuation:
        string = string.replace(char, "")

    return string


string = "the Zen of Python, by Tim Peters. beautiful is better than ugly." \
         " explicit is better than implicit. simple is better than complex."

print(remove_punctuation(string))

basically we do the replacing one per each character in punctuation.

solution number 2:

If you wanna get better performance you can .translate the string:

def remove_punctuation(string):
    punctuation = [",", "."]
    table = str.maketrans(dict.fromkeys(punctuation))
    return string.translate(table)

In translation, each key that has the value of None in the table, will be removed from the string. fromkeys will create a dictionary from an iterable and put None as their values (it’s the default value)