How to parse a part of a link in python?

[atomkarinca]

Hi everyone. How can I crop a part of a link in python? For example, let's say the link is http://www.youtube.com/watch?v=FRnrKzOrp7M and I want to get FRnrKzOrp7M from that link. How do I go about doing that? Thanks.

[Acglaphotis]

string = "http://www.youtube.com/watch?v=FRnrKzOrp7M"
newString = string.replace("http://www.youtube.com/watch?v=", "") 

newString only has FRnrKzOrp7M.

[atomkarinca]

Thanks for the quick reply

[Can+~]

I would've suggested using regular expressions for that. Like looking for the "?v=_______" with it, since youtube can have different flags like "?locale=" for another language, etc.

[atomkarinca]

How can I do that? What if -like you said- there was another flag?

[a9bejo]

http://www.amk.ca/python/howto/regex/

[Acglaphotis]

Heres a link on how to use regulars expression on python (kinda hard though):

http://www.amk.ca/python/howto/regex/

Or you could replace the "http://www.youtube.com/watch?v=" with "http://www.youtube.com/watch?*="

[atomkarinca]

I would've suggested using regular expressions for that. Like looking for the "?v=_______" with it, since youtube can have different flags like "?locale=" for another language, etc.

How can I use this with replace() ? Can you give a simple example?

[Can+~]

More about Regular expressions:
http://docs.python.org/dev/howto/regex.html

*edited*

import re
ytburl = "http://www.youtube.com/watch?v=FRnrKzOrp7M"
regexp = "v=\\w*" 

#It's a good idea to compile it if you're gonna use it more than once.
regexp = re.compile(regexp, re.IGNORECASE)
result = regexp.search(ytburl)

if (result):
    print "String: %s" % result.group()
else:
    print "Not found." 

Result:

String: v=FRnrKzOrp7M


------------------
(program exited with code: 0)
Press return to continue

I'm sure there's a lot of improvement you could do to the regular expression like using {7,} to specify a minimum of repetitions instead of using the *.

[mssever]

In Ruby, you would do something like

/v=([^&])/.match url
video_id = $1

The regular expression (between, but not including, the slashes) should be the same in Python. $1 is the contents of the first perenthesized part of the regex. I don't know how to access that data in Python, but you should be able to find it easily enough. The regex is the hardest part of this.