get substring from the main string Python

Question

I have a string and I want to extract a substring from that main string

Some sample strings are:

http://domain.com/xxxxx/xxxxxxxx?tags=%7C105651%7C102496&Asidebar=1&dnr=y
http://domain.com/xxxxx/xxxxxx?tags=%7C12784%7C102496&index=28&showFromBeginning=true&

I want to get the tags value.

In this case:

val = %7C105651%7C102496

val = %7C12784%7C102496

Is there any chance to get that?

Edit

tags = re.search('tags=(.+?)&Asidebar', url)
print tags
if tags:
    found = tags.group(1)
    print (found)
output: None

Note: I've just tried to get something from the first string only

There is a great chance. Can you show us what you came up with so far? — Anthony Forloney
– Anthony Forloney, Commented Nov 25, 2014 at 13:46

falsetru · Accepted Answer · 2014-11-25 13:48:23Z

3

Using urlparse.urlparse and cgi.parse_qs (Python 2.x):

>>> import urlparse
>>> import cgi
>>>
>>> s = 'http://domain.com/xxxxx/xxxxxxxx?tags=%7C105651%7C102496&Asidebar=1&dnr=y'
>>> cgi.parse_qs(urlparse.urlparse(s).query)
{'dnr': ['y'], 'Asidebar': ['1'], 'tags': ['|105651|102496']}
>>> cgi.parse_qs(urlparse.urlparse(s).query)['tags'][0]
'|105651|102496'

In Python 3.x, use urllib.parse.urlparse and urllib.parse.parse_qs:

>>> import urllib.parse
>>>
>>> s = 'http://domain.com/xxxxx/xxxxxxxx?tags=%7C105651%7C102496&Asidebar=1&dnr=y'
>>> urllib.parse.parse_qs(urllib.parse.urlparse(s).query)['tags'][0]
'|105651|102496'

answered Nov 25, 2014 at 13:48

falsetru

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3 Comments

MMK Over a year ago

really thanks. but it seems it is pretty advance.. I'm new to PY and will stick to easyone Thanks for your effort

falsetru Over a year ago

@MMK, Isn't this easy? The function will care edge case for you. Try http://domain.com/xxxxx/xxxxxxxx?tags=%7C105651%7C102496 / http://domain.com/xxxxx/xxxxxxxx?tags=

MMK Over a year ago

sure..I'm checking it.

Avinash Raj · Accepted Answer · 2014-11-25 13:52:09Z

3

You're almost there. You don't need to write Asidebar in your regex. Because in your second input string, there isn't a substring called Asidebar.

tags = re.search('tags=(.+?)&', url)
if tags:
    found = tags.group(1)
    print (found)

answered Nov 25, 2014 at 13:52

Avinash Raj

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