Difference between revisions of "PreludeTour"
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Revision as of 13:41, 26 October 2009
A Tour of the Haskell Prelude
- abs
| type: | abs :: Num a => a -> a
|
| description: | returns the absolute value of a number. |
| definition: | abs x
| x >= 0 = x
| otherwise = -x
|
| usage: | Prelude> abs (-3) 3 |
- all
| type: | all :: (a -> Bool) -> [a] -> Bool
|
| 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. |
| definition: | all p xs = and (map p xs)
|
| usage: | Prelude> all (<11) [1..10] True Prelude> all isDigit "123abc" False |