How can I use regular expression or any other method to sub a specific pattern of a string (python 2.7)?

Question

So the string url I have is 'http://helloworld.net/b/c/3?nw=174057&csid=fire.clan.com/gram/&din=&rand=52710&w=400&h=112' . This is in python 2.7.

Now the parameter rand in the url keeps changing and is always a 5 number length so it can be rand=12345 or 99999 and etc

Now I want to change that in this case ( 'rand=52710' ) to something like 'sub' or just ''

I have made attempts at this by using https://developers.google.com/edu/python/regular-expressions but didn't come up with a solid solution

Any help would be appreciated thanks.

Answer 1

Using Regex .

Ex:

import re
u = 'http://helloworld.net/b/c/3?nw=174057&csid=fire.clan.com/gram/&din=&rand=52710&w=400&h=112'
print re.sub("rand\=\d+", "SUB", u)

Output:

http://helloworld.net/b/c/3?nw=174057&csid=fire.clan.com/gram/&din=&SUB&w=400&h=112

Answer 2

Without regex, assuming that your claim " now the parameter rand in the url keeps changing and is always a 5 number length so it can be rand=12345 or 99999 " holds true:

url = "http://helloworld.net/b/c/3?csid=fire.clan.com/gram/&din=&rand=52710&w=400&h=112"
index = url.rfind("rand=")
if index != -1:
    url = url[:index] + url[index+11:]  # add 'sub' between url parts if you want it
# http://helloworld.net/b/c/3?csid=fire.clan.com/gram/&din=&w=400&h=112