Philip Semanchuk wrote: > > On Sep 5, 2010, at 1:09 PM, Roy Smith wrote: > >> I'm using httplib, and want to get the Location header from the >> response. The getheaders() method gives you back a list of (name, >> value) tuples. It would be a lot more convenient if it gave you >> back a >> dict, but it is what it is. >> >> Anyway, I came up with: >> >> location = [t[1] for t in headers if t[0] == 'location'][0] >> >> which works, but is getting on towards the cryptic end of things. Is >> there a better idiom for this? > > Are you concerned about efficiency? If it's not important, being less > terse would make it less cryptic: > location = None > for name, value in headers: > if name == "location": > location = value > break
This is actually more efficient because unlike Roy's (and your other solution) it doesn't build a list, and it doesn't waste cycles in the loop once the location is found. You can write it as a generator expression like so: location = next((value for name, value in headers if name == "location"), None) But just converting the headers to a dict is clearer and probably even faster because it moves the loop from Python to C. > If you prefer terse, IMHO this is less cryptic (but untested): > > location = [value for name, value in headers if name == 'location'] > [0] > > > Be careful if you decide to turn the list of tuples into a dictionary. > HTTP headers can repeat and straightforward code to turn the (name, > value) pairs into a dict could end up overwriting data. -- http://mail.python.org/mailman/listinfo/python-list
