[Haskell-cafe] Removing alternate items from a list

[Bill Atkins]

alts :: [a] -> [a]
alts xs = map fst . filter snd $ zip xs (cycle [False, True])

Prelude> alts [0, 1..5]
[1,3, 5]

On Sunday Jun 6, 2010, at 10:46 AM, R J wrote:

> What's the cleanest definition for a function f :: [a] -> [a] that takes a list and returns the same list, with alternate items removed?  e.g., f [0, 1, 2, 3, 4, 5] = [1,3,5]?
> 
> 
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