[Tutor] dictionary swittching

[Kalle Svensson]

[Jörg Wölke]
> if "a" in x.keys():
> 	print "Does that do what you want?"

Don't do that, it's O(N).  First it gets all the keys from the dict,
which is linear time.  Then it does a linear search through the
resulting list to see if "a" is a member.  Use

if x.has_key("a"):

which is O(1), it uses hashing.

if "a" in x:
does the right thing in Python 2.2.

Peace,
  Kalle
-- 
Kalle Svensson, http://www.juckapan.org/~kalle/
Student, root and saint in the Church of Emacs.