Difference between revisions of "FP Laboratory 3"
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* Create a function that computes length of a list. | * Create a function that computes length of a list. | ||
<syntaxhighlight lang="Haskell">length' :: [a] -> Int</syntaxhighlight> | <syntaxhighlight lang="Haskell">length' :: [a] -> Int</syntaxhighlight> | ||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | length' :: [a] -> Int | ||
| + | length' [] = 0 | ||
| + | length' (_:xs) = 1 + length' xs | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that sums the list of integers. | * Create a function that sums the list of integers. | ||
<syntaxhighlight lang="Haskell">sumIt :: [Int] -> Int</syntaxhighlight> | <syntaxhighlight lang="Haskell">sumIt :: [Int] -> Int</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | sumIt :: [Int] -> Int | ||
| + | sumIt [] = 0 | ||
| + | sumIt (x:xs) = x + sumIt xs | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that returns the first element in the list. | * Create a function that returns the first element in the list. | ||
<syntaxhighlight lang="Haskell">getHead :: [a] -> a</syntaxhighlight> | <syntaxhighlight lang="Haskell">getHead :: [a] -> a</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | getHead :: [a] -> a | ||
| + | getHead (x:_) = x | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that returns the last element in the list. | * Create a function that returns the last element in the list. | ||
<syntaxhighlight lang="Haskell">getLast :: [a] -> a</syntaxhighlight> | <syntaxhighlight lang="Haskell">getLast :: [a] -> a</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | getLast :: [a] -> a | ||
| + | getLast (x:xs) | length xs == 0 = x | ||
| + | | otherwise = getLast xs | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that checks if an element is a member of the list. | * Create a function that checks if an element is a member of the list. | ||
<syntaxhighlight lang="Haskell">isElement :: Eq a => a -> [a] -> Bool</syntaxhighlight> | <syntaxhighlight lang="Haskell">isElement :: Eq a => a -> [a] -> Bool</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that returns the list without the first element. | * Create a function that returns the list without the first element. | ||
<syntaxhighlight lang="Haskell">getTail :: [a] -> [a]</syntaxhighlight> | <syntaxhighlight lang="Haskell">getTail :: [a] -> [a]</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that returns the list without the last element. | * Create a function that returns the list without the last element. | ||
<syntaxhighlight lang="Haskell">getInit :: [a] -> [a]</syntaxhighlight> | <syntaxhighlight lang="Haskell">getInit :: [a] -> [a]</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that merge two lists into one list. | * Create a function that merge two lists into one list. | ||
<syntaxhighlight lang="Haskell">combine :: [a] -> [a] -> [a]</syntaxhighlight> | <syntaxhighlight lang="Haskell">combine :: [a] -> [a] -> [a]</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that finds the maximum in the list of integers. | * Create a function that finds the maximum in the list of integers. | ||
<syntaxhighlight lang="Haskell">max' :: [Int] -> Int</syntaxhighlight> | <syntaxhighlight lang="Haskell">max' :: [Int] -> Int</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that reverse a list. | * Create a function that reverse a list. | ||
<syntaxhighlight lang="Haskell">reverse' :: [a] -> [a]</syntaxhighlight> | <syntaxhighlight lang="Haskell">reverse' :: [a] -> [a]</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
| + | |||
* Create a function that product scalar multiplication if two vectors. | * Create a function that product scalar multiplication if two vectors. | ||
<syntaxhighlight lang="Haskell">scalar :: [Int] -> [Int] -> Int</syntaxhighlight> | <syntaxhighlight lang="Haskell">scalar :: [Int] -> [Int] -> Int</syntaxhighlight> | ||
| + | |||
| + | <div class="mw-collapsible mw-collapsed" data-collapsetext="Hide solution" data-expandtext="Show solution"> | ||
| + | <syntaxhighlight lang="Haskell"> | ||
| + | </syntaxhighlight> | ||
| + | </div> | ||
| + | <div style="clear:both"></div> | ||
Revision as of 08:39, 24 September 2020
Usage of lists
Find out the results of the following operations:
[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]
Simple functions working with list
Implement following functions:
- Create a function that computes length of a list.
length' :: [a] -> Int
length' :: [a] -> Int
length' [] = 0
length' (_:xs) = 1 + length' xs
- Create a function that sums the list of integers.
sumIt :: [Int] -> Int
sumIt :: [Int] -> Int
sumIt [] = 0
sumIt (x:xs) = x + sumIt xs
- Create a function that returns the first element in the list.
getHead :: [a] -> a
getHead :: [a] -> a
getHead (x:_) = x
- Create a function that returns the last element in the list.
getLast :: [a] -> a
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
- Create a function that returns the list without the first element.
getTail :: [a] -> [a]
- Create a function that returns the list without the last element.
getInit :: [a] -> [a]
- Create a function that merge two lists into one list.
combine :: [a] -> [a] -> [a]
- Create a function that finds the maximum in the list of integers.
max' :: [Int] -> Int
- Create a function that reverse a list.
reverse' :: [a] -> [a]
- Create a function that product scalar multiplication if two vectors.
scalar :: [Int] -> [Int] -> Int
