-- Prelude
5 + 2 == 8
5 * 2 == 10
5 - 2 == 3
5 / 2 == 2.5
( True || False ) == True
( True && False ) == False
not True == False
succ 'c' == 'd'
min 4 5 == 4
max 'a' 'z' == 'z'
div 92 3 == 30
mod 14 5 == 4
[1,2,3] ++ [4,5] == [1,2,3,4,5]
'a':" long time" == "a long time"
"abcdef" !! 2 == 'c'
( [1,2,3] < [1,2,4] ) == True
( "bbc" > "abc" ) == True
( [1,2,3] <= [1,2,4] ) == True
( "bbc" >= "abc" ) == True
( "abc" == "abc" ) == True
(1.0 /= 1.5) == True
head [1..] == 1
tail [1,2,3] == [2,3]
init [1,2,3,4] == [1,2,3]
length ['a'..'z'] == 26
null [] == True
reverse [1,2,3] == [3,2,1]
take 3 [1..] == [1,2,3]
drop 7 [1..10] == [8,9,10]
maximum [1,10,2] == 10
minimum [3,2,4] == 2
sum [1,10,100] == 10
product [2,3,4] == 24
elem 4 [1,2,3,4,5] == True
take 10 ( cycle "abc") == "abcabcabca"
take 5 ( repeat 'x') == "xxxxx"
replicate 5 'x' == "xxxxx"
odd 5 == True
even 8 == True
fst (1,'A') == 1
snd (1,'A') == 'A'
zip [1..] "ABC" == [(1,'A'),(2,'B'),(3,'C')]
show 4.25 == "4.25"
(read "4" :: Int) == 4
(minBound :: (Bool, Int, Char)) == (False,-9223372036854775808,'\NUL')
(maxBound :: (Bool, Int, Char)) == (True,9223372036854775807,'\1114111')
fromIntegral (div 5 3) + 1.5 == 2.5
compare 1 2 == LT
zipWith (*) [1..3] [10,20,30] == [10,40,90]
flip (++) "DEF" "ABC" == "ABCDEF"
map (10-) [1..3] == [9,8,7]
filter (<3) [1..10] == [1,2]
takeWhile (/= 'd') "abracadabra" == "abraca"
foldl (-) 10 [1,2] == 7
foldr (-) 10 [1,2] == 9
foldl1 (-) [10,1,2] == 7
foldr1 (-) [1,2,10] == 9
and [True, False, True] == False
or [True, False, True] == True
scanl (+) 0 [1,2,3] == [0,1,3,6]
scanr (+) 0 [1,2,3] == [6,5,3,0]
scanl1 (+) [1,2,3] == [1,3,6]
scanr1 (+) [1,2,3] == [6,5,3]
abs (-9) == 9
sqrt 9 == 3.0
negate 3.0 == -3.0
negate $ sqrt $ abs (-9) == -3.0
(negate . sqrt . abs) (-9) == -3.0
id "itself" == "itself"
fmap (+1) [1,2,3] == [2,3,4]
fmap (+1) (Just 100) == Just 101
words "I don't like it!" == ["I","don't","like","it!"]
unwords ["A","big","dog"] == "A big dog"
-- IO
putStrLn 文字列 文字列出力+改行
putStr 文字列 文字列出力
putChar 文字 一文字出力
s <- getLine 一行読み込み改行は削除
print 値 値を文字列化(show)して出力
sequence I/Oアクションリスト I/Oアクションのリストを順に実行、結果のリストを返す
-- データ型
data Bool = True | Flase
data Maybe a = Nothing | Just a
data Either a b = Left a | Right a
--
:type print -- print :: Show a => a -> IO ()
--
-- import qualified Data.List as List
List.nub "abracadabra" == "abrcd"
List.sort [9,8..0] == [0,1,2,3,4,5,6,7,8,9]
List.group "aaabbcca" == ["aaa","bb","cc","a"]
List.tails [1,2,3] == [[1,2,3],[2,3],[3],[]]
List.isPrefixOf "Hi" "Hiroshi!" == True
List.any (== 'c') "abcdef" == True
List.isInfixOf "abc" "xxabcyy" == True
List.foldl' -- foldl の正格(Strict evaluation)版
List.foldr' -- foldr の正格(Strict evaluation)版
List.find (== 0) [1,2,3] == Nothing
-- import qualified Data.Char as Char
Char.ord 'A' == 65
Char.chr 97 == 'a'
Char.digitToInt '2' == 2
Char.toUpper 'a' == 'A'
-- import qualified Data.Map as Map
Map.fromList [(1,"One"), (2,"Two")] == fromList [(1,"One"),(2,"Two")]
Map.lookup 2 $ Map.fromList [(1,"A"), (2,"B")] == Just "B"
Map.fromListWith (+) [("A",1),("B",2),("A",3)] == fromList [("A",4),("B",2)]
「すごいHaskellたのしく学ぼう!」を読んでいて出てきた関数のメモ
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