Difference between revisions of "FP Laboratory 3/cs"
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(Created page with "Zjistěte jaké jspou výsledky následujících operací:") |
(Created page with "== Jwednoduché funkce pracující se seznamy == Implementujte následující funkce: * Vytvořte funkci, která vypočítá délku seznamu.") |
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− | == | + | == Jwednoduché funkce pracující se seznamy == |
− | + | Implementujte následující funkce: | |
− | * | + | * Vytvořte funkci, která vypočítá délku seznamu. |
<syntaxhighlight lang="Haskell">length' :: [a] -> Int</syntaxhighlight> | <syntaxhighlight lang="Haskell">length' :: [a] -> Int</syntaxhighlight> |
Revision as of 08:27, 19 October 2021
Usage of lists
Zjistěte jaké jspou výsledky následujících operací:
[3,2,1] > [2,1,0]
[3,2,1] > [2,10,100]
[3,4,2] > [3,4]
[3,4,2] > [2,4]
[3,4,2] == [3,4,2]
Jwednoduché funkce pracující se seznamy
Implementujte následující funkce:
- Vytvořte funkci, která vypočítá délku seznamu.
length' :: [a] -> Int
*Main> length' "ABCD"
4
- Create a function that sums the list of integers.
sumIt :: [Int] -> Int
*Main> sumIt [1,2,3]
6
- Create a function that returns the first element in the list.
getHead :: [a] -> a
*Main> getHead [1,2,3]
1
- Create a function that returns the last element in the list.
getLast :: [a] -> a
*Main> getLast [1,2,3]
3
getLast :: [a] -> a
getLast [x] = x
getLast (x:xs) = getLast xs
getLast' :: [a] -> a
getLast' (x:xs) | length xs == 0 = x
| otherwise = getLast' xs
- Create a function that checks if an element is a member of the list.
isElement :: Eq a => a -> [a] -> Bool
*Main> isElement 2 [1,2,3]
True
isElement :: Eq a => a -> [a] -> Bool
isElement _ [] = False
isElement a (x:xs) | a == x = True
| otherwise = isElement a xs
- Create a function that returns the list without the first element.
getTail :: [a] -> [a]
*Main> getTail [1,2,3]
[2,3]
- Create a function that returns the list without the last element.
getInit :: [a] -> [a]
*Main> getInit [1,2,3]
[1,2]
- Create a function that merge two lists into one list.
combine :: [a] -> [a] -> [a]
*Main> combine [1,2,3] [4,5]
[1,2,3,4,5]
- Create a function that finds the maximum in the list of integers.
max' :: [Int] -> Int
*Main> max' [3,1,7,5]
7
max' :: [Int] -> Int
max' [x] = x
max' (x:y:z) | x > y = max' (x:z)
| otherwise = max' (y:z)
max'' :: [Int] -> Int
max'' (y:ys) = tmp y ys where
tmp a [] = a
tmp a (x:xs) | x > a = tmp x xs
|otherwise = tmp a xs
- Create a function that reverse a list.
reverse' :: [a] -> [a]
*Main> reverse' [3,1,7,5]
[5,7,1,3]
reverse' :: [a] -> [a]
reverse' [] = []
reverse' (x:xs) = (reverse' xs) ++ [x]
reverse'' :: [a] -> [a]
reverse'' n = tmp n []
where tmp [] ys = ys
tmp (x:xs) ys = tmp xs (x:ys)
- Create a function that product scalar multiplication if two vectors.
scalar :: [Int] -> [Int] -> Int
*Main> scalar [1,2,3] [4,5,6]
32