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Haskell 勉強記録 9 日目

今日は 第6章:モジュール 標準モジュールの関数で問題を解く (位置 2262/11175)まで読み進めました。

今まで出てきた関数

-- 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

-- Data.List
words
nub "abracadabra"          == "abrcd"
sort [9,8..0]              == [0,1,2,3,4,5,6,7,8,9]
words "I don't like it!"   == ["I","don't","like","it!"]
group "aaabbcca"           == ["aaa","bb","cc","a"]
tails [1,2,3]              == [[1,2,3],[2,3],[3],[]]