Remove special characters and replace spaces with “-”

Question

I'm trying to make a directory that is okay to appear in a URL. I want to ensure that it doesn't contain any special characters and replace any spaces with hyphens.

from os.path import join as osjoin
def image_dir(self, filename):
    categorydir = ''.join(e for e in  str(self.title.lower()) if e.isalnum())
    return "category/" + osjoin(categorydir, filename)

It's removing special characters however I'd like use .replace(" ", "-") to swap out spaces with hyphens

Answer 1

The best way is probably to use the slugify function which takes any string as input and returns an URL-compatible one, yours is not an URL but it will do the trick, eg:

>>> from django.utils.text import slugify
>>> slugify(' Joel is a slug ')
'joel-is-a-slug'

Answer 2

Why don't you use the quote function?

import urllib.parse

urlllib.parse.quote(filename.replace(" ", "-"), safe="")

Answer 3

You can create this functions and call remove_special_chars(s) to do it:

def __is_ascii__(c):
    return (ord(c) < 128)


def remove_special_chars(s):
    output = ''

    for c in s:
        if (c.isalpha() and __is_ascii__(c)) or c == ' ':
            output = output + c
        else:
            if c in string.punctuation:
                output = output + ' '

    output = re.sub(' +', ' ', output)
    output = output.replace(' ', '-')

    return output

It will remove each non-ASCII character and each element in string.punctuation

EDIT: This function will substitute each element in string.punctuation with a '-', if you want you can substitute ' ' with '' in the else statement to merge the two parts of the string before and after the punctuation element.