Replacing a blank

Question

i am building a URL and replacing all the spaces with +

url.replace(' ','+')

for some reason it is not replacing any of the white spaces!

anyone know what is wrong?

Answer 1

The replace function doesn't replace anything in-place - you need to assign it:

url = url.replace(' ','+')

Answer 2

You are probbly still looking at the old url. replace returns new string with replaced values. Try:

url = url.replace(' ', '+')

Answer 3

Aside:

If you are encoding a query or path component for inclusion in a URL, you will need to do more than simply replacing the space character. There are many other characters which won't fit unencoded into a URL component, and which may break the URL if you try. These have to be replaced by %nn hexadecimal escape sequences.

Use urllib to take care of URL-encoding rather than trying to do it yourself with string methods. For example:

>>> import urllib
>>> param= 'Hello world!'
>>> url= 'http://www.example.com/script.py?a='+urllib.quote_plus(param)
>>> url
'http://www.example.com/script.py?a=Hello+world%21'

(urllib.quote_plus() is designed explicitly for form parameters in the query string, so it'll use + for spaces, as opposed to %20 which urllib.quote() produces. %20 works in path components as well as query components, so it's a bit safer than +, but slightly more messy visually.)

If you have more than one parameter, use urlencode() on a dictionary. This is generally easier to read than trying to stick strings together:

>>> params= {'foo': 'bar', 'bof': 'Hello world!'}
>>> url= 'http://www.example.com/script.py?'+urllib.urlencode(params)
>>> url
'http://www.example.com/script.py?foo=bar&bof=Hello+world%21'