Parse value from string

Question

I have:

url = 'http://example.com/json?key=12345&lat=52.370216&lon=4.895168&status=upcoming&radius=20&offset=0'

How can I parse the value 20 for the parameter radius?

I think it is not possible with urlparse.parse_qs(), isn't it? Also is there a better way rather than using regex?

Answer 1

Yes, use parse_qs():

Parse a query string given as a string argument (data of type application/x-www-form-urlencoded). Data are returned as a dictionary. The dictionary keys are the unique query variable names and the values are lists of values for each name.

>>> from urlparse import parse_qs
>>> url = 'http://example.com/json?key=12345&lat=52.370216&lon=4.895168&status=upcoming&radius=20&offset=0'
>>> parse_qs(url)['radius'][0]
'20'

UPD: as @DanielRoseman noted (see comments), you should first pass url through urlparse:

>>> from urlparse import parse_qs, urlparse
>>> parse_qs(urlparse(url).query)['radius'][0]
'20'

• Daniel Roseman: This won't work if radius was the first parameter after the ?, because parse_qs doesn't ignore the rest of the URL. Really you should pass it through urlparse first: urlparse.parse_qs(urlparse.urlparse(url).query)['radius']
• alecxe: @DanielRoseman didn't know that. Thank you, will include into the answer.