index()-like behavior that returns all occurences...

Paul Jackson pj at sgi.com
Wed Dec 19 23:39:11 CET 2001


|> x = [ [1], [1,2], [], [1,2,3], [], [2], [12] ]
|> 
|> I want to find the index of all of the empty lists. In other words, I'd 
|> like a function foo that would behave like this:
|> 
|>  >> foo(x)
|> [2 4]

Well, you could do a one liner with the lambda, map, zip, filter routines:

    map (lambda x: x[0], filter (lambda x: not x[1], zip (range(len(x)), x)))

But this has _got_ to be less readable than the simple for loop,
even to whomever it was that championed getting map, reduce and
filter into the Python language in the first place.
-- 

                          I won't rest till it's the best ...
			  Manager, Linux Scalability
                          Paul Jackson <pj at sgi.com> 1.650.933.1373



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