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isLeapYear :: Int -> Bool | |
isLeapYear year = | |
if year `mod` 4 == 0 | |
then | |
if year `mod` 100 == 0 | |
then | |
if year `mod` 400 == 0 | |
then True | |
else False | |
else True |
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atMay :: [a] -> Int -> Maybe a | |
[] `atMay` _ = None | |
[x] `atMay` 0 = Just x | |
(_:xs) `atMay` i = xs `atMay` (i - 1) |
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(!!) :: [a] -> Int -> a | |
[] !! _ = undefined | |
[x] !! 0 = x | |
(_:xs) !! i = xs !! (i - 1) |
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add :: a -> [a] -> [a] | |
add x xs = x : xs | |
-- it is more common to write as | |
-- add = (:) | |
remove :: (Eq a) => a -> [a] -> [a] | |
remove _ [] = [] | |
remove t (x:xs) = if t == x then remove t xs else remove t (x:xs) | |
-- you can also write it as a fold | |
-- remove t = foldr (\x xs -> if x == t then xs else x:xs) [] |
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mySum :: [Int] -> Int | |
mySum [] = 0 | |
mySum (x:xs) = x + mySum xs |
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-– Empty list | |
[] | |
–- We use the cons operator (:) to combine the element 3 (an integer) | |
-- and an empty list (which can take on the type of integer list) | |
3 : [] | |
-- The cons operator is right-associative. (3 : []) is also of type integer | |
-- list, we use the cons operator again to add the element 2 in front of it | |
2 : (3 : []) | |
-- The cons operator is right-associative. (2 : 3 : []) is also of type integer | |
-- list, we use the cons operator again to add the element 1 in front of it |
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data [] a = [] | a : [a] |
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const list = []; | |
list.push(1); | |
list.push(2); | |
list.push(3); |
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var list = new List<int> { 1, 2, 3 }; | |
// Syntactic sugar of | |
var list = new List<int>(); | |
list.Add(1); | |
list.Add(2); | |
list.Add(3); |
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join :: Monad m => m (m a) -> m a |