How do I replace whitespaces with underscore and vice versa?

Question

I want to replace whitespace with underscore in a string to create nice URLs. So that for example:

"This should be connected" becomes "This_should_be_connected"

I am using Python with Django. Can this be solved using regular expressions?

Answer 1

You don't need regular expressions, Python has a string method that does what you need:

mystring.replace (" ", "_")

Answer 2

Using the re module:

import re
re.sub('\s+', '_', "This should be connected") # This_should_be_connected
re.sub('\s+', '_', 'And     so\tshould this')  # And_so_should_this

Unless you have multiple spaces or other whitespace possibilities as above, you may just wish to use string.replace as others have suggested.

Answer 3

use string's replace method:

"this should be connected".replace(" ", "_")

"this_should_be_disconnected".replace("_", " ")

Answer 4

Replacing spaces is fine, but I might suggest going a little further to handle other URL-hostile characters like question marks, apostrophes, exclamation points, etc.

Also note that the general consensus among SEO experts is that dashes are preferred to underscores in URLs.

def urlify(s):

     # Remove all non-word characters (everything except numbers and letters)
     s = re.sub(r"\W", '', s)

     # Replace all runs of whitespace with a single dash
     s = re.sub(r"\s+", '-', s)

     return s



# Prints: I-cant-get-no-satisfaction"
print urlify("I can't get no satisfaction!")

Answer 5

Django has a 'slugify' function which does this, as well as other URL-friendly optimisations. It's hidden away in the defaultfilters module.

>>> from django.template.defaultfilters import slugify
>>> slugify("This should be connected")

this-should-be-connected

This isn't exactly the output you asked for, but IMO it's better for use in URLs.

Answer 6

I'm using the following piece of code for my friendly urls:

from unicodedata import normalize
from re import sub

def slugify(title):
    name = normalize('NFKD', title).encode('ascii', 'ignore').replace(' ', '-').lower()
    #remove `other` characters
    name = sub('[^a-zA-Z0-9_-]', '', name)
    #nomalize dashes
    name = sub('-+', '-', name)

    return name

It works fine with unicode characters as well.

Answer 7

Python has a built in method on strings called replace which is used as so:

string.replace(old, new)

So you would use:

string.replace(" ", "_")

I had this problem a while ago and I wrote code to replace characters in a string. I have to start remembering to check the python documentation because they've got built in functions for everything.

Answer 8

perl -e 'map { $on=$_; s/ /_/; rename($on, $_) or warn $!; } <*>;'

Match et replace space > underscore of all files in current directory

Answer 9

string.replace(' ', '_'); //only replaces the first instance of ' ' with '_'. this is wrong.
string.replace(/\s/g, '_'); //this is correct, replaces all instances of ' ' with '_'.