22 lines
550 B
Markdown
22 lines
550 B
Markdown
---
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title: List Comprehensions
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---
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## List Comprehensions
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List comprehensions are a powerful tool in haskell for working with sets.
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```haskell
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someNumbers :: [Int] # a list of integers containing, 1, 2 and 3
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someNumbers = [1,2,3]
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allLower :: [Char]
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allLower = [toLower c | c <- "Hello, World!" ]
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parity :: [(Int, Boolean)]
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parity = [ ( x , even x ) | x <- [1,2,3] ]
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```
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Parity produces the following set: `[ (1, False), (2, True), (3, False) ]`
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The right hand side of the list comprehension is composed of two parts; a generator and guards.
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