Difference between revisions of "PreludeTour"
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Tomjaguarpaw (talk | contribs) (Tour was cut short for some reason) |
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| − | == A Tour of the Haskell Prelude == |
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| − | ;<span id="abs">'''abs'''</span>: |
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| − | {| border="0" cellpadding="4" |
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| − | |- |
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| − | | ''type:'' || <hask>abs :: Num a => a -> a</hask> |
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| − | |- |
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| − | | ''description:'' || returns the absolute value of a number. |
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| − | |- |
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| − | | ''definition:'' |
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| − | | <haskell> |
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| − | abs x |
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| − | | x >= 0 = x |
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| − | | otherwise = -x |
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| − | </haskell> |
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| − | |- |
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| − | | ''usage:'' |
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| − | | <pre> |
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| − | Prelude> abs (-3) |
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| − | 3 |
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| − | </pre> |
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| − | |} |
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| − | |||
| − | ;<span id="all">'''all'''</span>: |
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| − | {| border="0" cellpadding="4" |
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| − | |- |
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| − | | ''type:'' || <hask>all :: (a -> Bool) -> [a] -> Bool</hask> |
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| − | |- |
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| − | | ''description:'' || Applied to a predicate and a list, returns True if all elements of the list satisfy the predicate, and False otherwise. Similar to the function [[#any]]. |
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| − | |- |
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| − | | ''definition:'' |
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| − | | <haskell> |
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| − | all p xs = and (map p xs) |
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| − | </haskell> |
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| − | |- |
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| − | | ''usage:'' |
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| − | | <pre> |
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| − | Prelude> all (<11) [1..10] |
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| − | True |
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| − | Prelude> all isDigit "123abc" |
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| − | False |
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| − | </pre> |
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| − | |} |
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