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Why would I like to use Maybe instead of List?

Seeing the Maybe type is isomorphic to a multitude of null and singleton lists, why would anyone ever want to use the Maybe type when I could just use the lists to accommodate the absence?

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7 answers

Based on the existing (and correct) answers, I mentioned a style based answer.

Different types convey different intentions - a return Maybe ais a computation with the possibility of failure, and [a]may be non-determinism (or, more simply, a lot of possible return values).

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Maybe. - - .

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. , , , , Maybe s, listToMaybe :

listToMaybe :: [a] -> Maybe a
listToMaybe [] = Nothing
listToMaybe (a:_) = Just a

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Maybe, , none, .

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, , QuickCheck - .

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