Here is a very simple, very useful script to lookup a value in a list of lists. [sourcecode language="python"]

Define a procedure, lookup,

that takes two inputs:

- an index

- keyword

The procedure should return a list

of the urls associated

with the keyword. If the keyword

is not in the index, the procedure

should return an empty list.

index = [['corewheels', ['http://corewheelfitness.com', 'http://www.akrowheels.com']], ['computing', ['http://acm.org']]]

def lookup(index,keyword): for entry in index: if entry[0]==keyword: return entry[1] return []

print lookup(index,'corewheels') #>>> ['http://corewheelfitness.com', 'http://www.akrowheels.com'] [/sourcecode]