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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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| − |
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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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