端端舝

允仍中H 凶及仄仁悝廿丹ㄐ?
菴6梒乒斥亙奈伙
twitter: @wrist
facebook: ohashi.hiromasa

赻撩畿賡
? twitter ID: @wrist (忒忑)
? http://hiromasa.info
? 嶊虞(詢苺) ↙ 靡嘉挌(湮悝) ↙ 湮筅(扦頗�)
? 政婓扦頗�3爛醴
? 議丟奈市奈卞化秞�陓瘍�I燴及旃噶嶱逃支勻化引允

(哫�)湮筅PRML掂𤩸頗
? 辻迮悝�及辭�頗毛翋殼仄化引允
? 政婓媼掛蕾化
? Python卞方月犯奈正煦昴⻌嬡
? PRML掂𤩸頗
? �仄仁反☆湮筅 PRML掂𤩸頗★
匹弘弘勻化仁分今中
? 棒隙6/22(゜)

☆菴6梒:乒斥亙奈伙★及衙猁
? 乒斥亙奈伙(衙猁﹜奶件禾奈玄源楊)
? 㻢𨃨乒斥亙奈伙及憝杅匹�觳毛賤仁
? �g惤螿僅市它件玄
? 伉旦玄及婦漪瓚隅
? 做瘍汜傖?賤掂
? 淏跡卅酘�心煋心

衙猁適五
? 井勻仇中中杅毛�勾仃方丹
? Maybe, Just, Nothing
? 窣砑伉旦玄
? 正皿伙毛蚚中凶桶政
? Data.Map
? 乒斥亙奈伙及釬傖
? 蕆𦵴倰乒斥亙奈伙

乒斥亙奈伙午反
? 中仁勾井及憝杅支倰﹜倰弁仿旦卅升毛隅膽仄凶白央奶伙
? Haskell及皿伕弘仿丞反乒斥亙奈伙及摩磁
? 隅砱仄凶手及反俋窒尺巨弁旦禾奈玄褫夔

戊奈玉毛恚杅乒斥亙奈伙卞煦仃月瞳萸
? 嗣仁及�卅月皿伕弘仿丞井日妏尹月
? 浩磐磁午卅月仇午匹婬瞳蚚俶互詢引月
? 奪燴仄支允中

Haskell及㻢𨃨仿奶皮仿伉
? 恚杅及乒斥亙奈伙卞煦賃
? 乒斥亙奈伙仍午卞僕籵及醴腔毛厥勾憝杅﹜倰互隅膽
? ex. 伉旦玄紱釬﹜�K俴皿伕弘仿立件弘﹜恚匼杅
? 仇木引匹及梒及允屯化及憝杅﹜倰﹜倰弁仿旦反?
�化Prelude午中丹乒斥亙奈伙及珨窒

GHCi及皿伕件皿玄
? 犯白巧伙玄分午§Prelude> ※午卅勻化中月互﹜?
仇木反Prelude乒斥亙奈伙毛妏勻化中月午中丹砩庤
? GHCi奻匹§:m + Data.List§卅升午坻及乒斥亙奈伙毛奶件
禾奈玄允月午﹜桶尨反§Prelude Data.List> ※卞劐趙
? :show prompt匹桶尨﹜:set prompt匹劐載褫夔

GHCi奻匹反:show imports匹
import仄凶乒斥亙奈伙互�木月
GHCi> :m + Data.List Data.Map
GHCi> :show imports
import Prelude -- implicit
import Data.List
import Data.Map

乒斥亙奈伙及奶件禾奈玄
? import ModuleName 匹奶件禾奈玄
? 瞰: 伉旦玄笢及珨砩卅猁匼毛杅尹月憝杅及釬傖
? Data.List卞漪引木月nub憝杅毛妏蚚
? nub: List井日笭恚毛龰曰壺仁憝杅
import Data.List
!
numUniques :: (Eq a) => [a] -> Int
numUniques = length . nub

Hoogle
? Haskell及𨈘坰巨件斥件
? 憝杅靡﹜乒斥亙奈伙靡﹜倰扑弘生民乓井日𨈘坰褫夔

GHCi匹及奶件禾奈玄
? ghci> :m + Data.List
? ghci> :m + Data.List Data.Set -- 恚杅乒斥亙奈伙
? 乒斥亙奈伙毛奶件禾奈玄允月旦弁伉皿玄毛?
伕奈玉仄凶�磁反:m +毛妏丹斛猁反卅中

杻隅及憝杅及心奶件禾奈玄
? 杻隅及憝杅及心奶件禾奈玄
? import Data.List (nub, sort)
? 杻隅及憝杅眕俋毛奶件禾奈玄
? import Data.List hiding (nub) -- nub眕俋毛奶件禾奈玄

党�葆五奶件禾奈玄(quali?ed奶件禾奈玄)
? 靡ゴ及�磁毛旌仃月凶戶及辻�
? import quali?ed Data.Map
? Data.Map及?lter憝杅毛妏丹�磁?
Data.Map.?lter午失弁本旦允月斛猁衄
? import quali?ed Data.Map as M
? M.?lter匹失弁本旦匹五月

.栳呾赽
? 媼勾及蚚楊
? 党�葆五奶件禾奈玄仄凶乒斥亙奈伙及憝杅及統桽
? 憝杅磁傖栳呾赽
? 乒斥亙奈伙靡午憝杅靡及嶲卞諾啞毛諾仃內卞离中凶�磁
奶件禾奈玄今木凶憝杅﹜公丹匹卅仃木壬憝杅磁傖

㻢𨃨乒斥亙奈伙及憝杅匹�觳毛賤仁
? 㻢𨃨仿奶皮仿伉及乒斥亙奈伙卞漪引木月憝杅及畿賡
? 灍瞰毛�化中仁

�g惤毛杅尹月
? 恅趼蹈卞�仄化�g惤毛市它件玄仄凶中
? Data.List及words憝杅: 諾啞匹�g惤毛Еピ月
GHCi> words "hey these are the words in this sentence"
["hey","these","are","the","words","in","this","sentence"]
GHCi> words "hey these are the words in this sentence"
["hey","these","are","the","words","in","this","sentence"]
? Data.List及group憝杅: 蕕諉猁匼毛弘伙奈疋件弘
GHCi> group [1,1,1,1,2,2,2,2,3,3,2,2,2,5,6,7]
[[1,1,1,1],[2,2,2,2],[3,3],[2,2,2],[5],[6],[7]]

猁匼互蕕諉仄化中卅中�磁
? 丐日井元戶末奈玄允月仇午匹賤𢜪
? Data.List及sort憝杅毛瞳蚚
GHCi> group ["boom", "bip", "bip", "boom", "boom"]
[["boom"],["bip","bip"],["boom","boom"]]
GHCi> sort [5,4,3,7,2,1]
[1,2,3,4,5,7]
GHCi> sort ["boom", "bip", "bip", "boom", "boom"]
["bip","bip","boom","boom","boom"]

恅趼蹈毛�g惤伉旦玄卞煦賃仄末奈玄仄弘伙奈疋
件弘仄�g惤午堤政隙杅及正皿伙卞煦仃月憝杅
GHCi> :t words
words :: String -> [String]
GHCi> :t sort
sort :: Ord a => [a] -> [a]
GHCi> :t group
group :: Eq a => [a] -> [[a]]
GHCi> :t (ws -> (head ws, length ws))
(ws -> (head ws, length ws)) :: [a] -> (a, Int)
import Data.List
!
wordNums :: String -> [(String,Int)]
wordNums = map (ws -> (head ws, length ws)) . group . sort . words
GHCi> wordNums "wa wa wee wa"
[("wa",3),("wee",1)]

憝杅磁傖卅仄匹𤩸仁
? 丹歹丐嬤說分日仃ㄐ
import Data.List
!
wordNums :: String -> [(String,Int)]
wordNums xs = map (ws -> (head ws, length ws)) (group (sort (words xs)))

補仄翌及刓井日�毛抻允
? 2勾及伉旦玄毛忳仃龰曰﹜1勾醴及伉旦玄互2勾醴及伉旦玄及
升仇井卞漪引木化中月井毛捼屯月
? [3,4]反[1,2,3,4,5]卞漪引木化中月互[2,5]反漪引木化中卅中
? 𨈘坰�砓及伉旦玄毛haystack(補仄翌及刓)﹜?
𨈘坰仄凶中伉旦玄毛needle(�)午網少

源�
? Data.List及tails憝杅毛妏中伉旦玄及�tail毛龰腕
!
? Data.List及isPre?xOf毛妏中?
2勾醴及伉旦玄互1勾醴及伉旦玄匹宎引勻化中月井毛捼屯月
!
? Data.List及any匹猁匼及升木井互扴惤毛㦤凶允井毛捼屯月
GHCi> tails ※party" => ["party","arty","rty","ty","y",""]
GHCi> tails [1,2,3] => [[1,2,3],[2,3],[3],[]]
GHCi> "hawaii" ìsPrefixOf` "hawaii joe§ => True
GHCi> "haha" ìsPrefixOf` ※ha" => False
GHCi> "ha" ìsPrefixOf` ※ha" => True
GHCi> any (> 4) [1,2,3] => False
GHCi> any (=='F') "Frank Sobotka§ => True
GHCi> any (x -> x > 5 && x < 10) [1,4,11] => False

瞎心磁歹六月
? Data.List卞isIn?xOf午中丹肮元�釬及憝杅互ㄐ?
切仁仄斤丹ㄐ
import Data.List
!
isIn :: (Eq a) => [a] -> [a] -> Bool
needle ìsIn` haystack = any (needle ìsPrefixOf`) (tails haystack)
GHCi> "art" ìsIn` "party"
True
GHCi> [1,2] ìsIn` [1,3,5]
False

扑奈扒奈做瘍扔仿母
? 扑奈扒奈做瘍匹丟永本奈斥毛做瘍趙
? 恅趼蹈毛失伙白央矛永玄奻匹珨隅及杅分仃扑白玄
? Unicode恅趼�极卞�允月手及互釬木月
? Data.Char及憝杅毛妏蚚(ord憝杅, chr憝杅)
GHCi> :m + Data.Char
GHCi> ord ＆a' => 97
GHCi> chr 97 => 'a'
GHCi> map ord "abcdefgh"
=> [97,98,99,100,101,102,103,104]

扑白玄允月杅午恅趼蹈毛忳仃龰曰恅趼蹈笢及跪恅趼毛?
失伙白央矛永玄奻匹硌隅今木凶杅分仃ゴ源砃卞扑白玄允月憝杅
? encode憝杅
import Data.Char
!
encode :: Int -> String -> String
encode offset msg = map (c -> chr $ ord c + offset) msg
!
-- (chr . (+ offset) . ord)匹手褫
GHCi> encode 3 "hey mark§ => "kh|#pdun"
GHCi> encode 5 "please instruct your men§ => "uqjfxj%nsxywzhy%~tzw%rjs"
GHCi> encode 1 "to party hard§ => "up!qbsuz!ibse"

decode憝杅
import Data.Char
!
encode :: Int -> String -> String
encode offset msg = map (c -> chr $ ord c + offset) msg
!
decode :: Int -> String -> String
decode shift msg = encode (negate shift) msg
GHCi> decode 3 "kh|#pdun"
"hey mark"
GHCi> decode 5 "uqjfxj%nsxywzhy%~tzw%rjs"
"please instruct your men"
GHCi> decode 1 "up!qbsuz!ibse"
"to party hard"

foldl妏蚚媆及旦正永弁左奈田奈白伕奈
? foldl反丟乒伉及杻隅及薆郖毛妏中綎亢凶媆卞お仇月?
旦正永弁左奈田奈白伕奈巨仿奈毛竘五お仇允仇午互丐月
GHCi> foldl (+) 0 (replicate 100 1)
100
1000000 -- H掛分午仇仇匹stack overflow
10000000
-- 忒啋及穴扑件分午仇仇匹嘐引月(引今卞俋耋)

stack over?ow及燴蚕
? Haskell反綈晊啐�匹丐曰灍蕣及�呾反?
褫夔卅癹曰摽引匹竘五扥壬今木月
? foldl毛妏丹媆﹜跪旦氾永皿卞云中化?
失平亙丞伊奈正及�呾毛灍蕣卞反俴歹卅中
? 陔仄中�呾匹ゴ及磐彆毛統桽允月井手仄木卅中及匹?
丟乒伉奻卞珂晊壬仄卞仄凶�呾毛悵厥仄適仃月
? 丟乒伉毛妏中彆凶仄化旦正永弁左奈田奈白伕奈

foldl及�呾及�赽
? 100勀猁匼丐月午珂晊壬仄卞仄化中凶�呾互?
�化婬䔝腔卞俴歹木月及匹?
旦正永弁左奈田奈白伕奈毛竘五お仇允
foldl (+) 0 [1,2,3] =
foldl (+) (0 + 1) [2,3] =
foldl (+) ((0 + 1) + 2) [3] =
foldl (+) (((0 + 1 ) + 2) + 3) [] =
((0 + 1) + 2) + 3 =
(1 + 2) + 3 =
3 + 3 =
6

�呾毛珂晊壬仄卞仄卅中foldl
? 酘殏曰�心及跪旦氾永皿嶲匹�呾互綈晊今木內?
允什卞啐�今木月foldl 〞> 淏跡卅foldl
foldl' (+) 0 [1,2,3] =
foldl' (+) 1 [2,3] =
foldl' (+) 3 [3] =
foldl' (+) 6 [] =
6

Data.List及foldl＊
? foldl及淏跡卅田奈斥亦件
? foldl1卞逋仄化手foldl1＊午中丹淏跡卅田奈斥亦件互湔婓
GHCi> :m + Data.List
GHCi> foldl' (+) 0 (replicate 100000000 1)
100000000

? 籵曰毛餜中化中月午橾𠵿�互輪葆中化懂化晟中引仄凶
? ☆跪鳻及杅及磁�互40卞卅月郔場及赻�杅反睡井★
? 123卅日壬1+2+3=6, 匹反40卞卅月杅反ˋ
井勻仇中中杅毛�勾仃方丹

源�
? 杅毛竘杅午仄化忳仃龰曰跪鳻及磁�毛А戶月憝杅毛釬月
? show毛妏勻化杅毛恅趼蹈卞劐𡥼
? Data.Char及digitToInt毛妏勻化?
恅趼毛杅卞劐𡥼
? 仇木日毛妏勻化憝杅毛𤩸仁
? 跪鳻及磁�互40卞卅月郔場及杅毛抻允憝杅毛釬月
? Data.List及?nd憝杅毛妏丹
GHCi> show 124
"124"
GHCi> :m + Data.Char
GHCi> digitToInt '2'
2
GHCi> digitToInt 'F'
15
GHCi> digitToInt 'z'
*** Exception: ?
Char.digitToInt: not a digit 'z'

跪鳻及磁�毛А戶月憝杅
import Data.Char
import Data.List
!
digitSum :: Int -> Int
digitSum = sum . map digitToInt . show
GHCi> :t show
show :: Show a => a -> String
GHCi> :t (map digitToInt)
(map digitToInt) :: [Char] -> [Int]
GHCi> :t sum
sum :: Num a => [a] -> a
GHCi> :t (sum . (map digitToInt) . show)
(sum . (map digitToInt) . show) :: Show a => a -> Int

digitSum毛羥蚚仄凶磐彆互?
40午卅月郔場及杅毛抻允憝杅
? Data.List及?nd憝杅毛妏丹
!
? 菴珨竘杅反扴惤﹜菴媼竘杅反伉旦玄
? Maybe午反ˋ
GHCi> :t find
find :: (a -> Bool) -> [a] -> Maybe a

Maybe a倰
? Maybe a倰及�反0�井﹜切斤丹升1�及猁匼分仃毛厥化月
? 伉旦玄倰[a]互0�﹜1�﹜丐月中反手勻午𢶷刓及猁匼毛?
厥化月及卞侔化中月
? 囮㷍允月褫夔俶互丐月仇午及桶政卞妏蚚

Maybe a倰及�
? Nothing井Just x及升切日井
? Nothing
? 0�及猁匼毛厥勻化中月 = 睡手厥勻化中卅中午中丹�
? 諾伉旦玄卞侔化中月
? Just x
? Maybe a倰及x毛悵厥仄化中月仇午毛桶政

方仁煦井日卅中及匹倰毛捼屯月
GHCi> Nothing
Nothing
GHCi> :t Nothing
Nothing :: Maybe a
GHCi> Just "hey"
Just "hey"
GHCi> Just 3
Just 3
GHCi> :t Just "hey"
Just "hey" :: Maybe [Char]
GHCi> :t Just 3
Just 3 :: Num a => Maybe a
GHCi> :t Just True
Just True :: Maybe Bool

?nd及�釬
? 扴惤毛㦤凶允猁匼互�勾井勻凶日﹜公及猁匼毛Just匹
仿永皿仄凶手及互殿今木月
? �勾井日卅仃木壬Nothing互殿今木月
GHCi> :t find
find :: (a -> Bool) -> [a] -> Maybe a
GHCi> find (> 4) [3,4,5,6,7]
Just 5
GHCi> find odd [2,4,6,8,9]
Just 9
GHCi> find (=='z') "mjolnir"
Nothing

跪鳻及磁�互40卞卅月?
郔場及杅毛�勾仃月憝杅
? 珂最灍蚾仄凶digitSum憝杅午?nd毛瞎心磁歹六月
import Data.List
import Data.Char
!
!
firstTo40 :: Maybe Int
firstTo40 = find (x -> digitSum x == 40) [1..]
GHCi> firstTo40
Just 49999

磁��毛n午仄化珨啜趙
import Data.List
import Data.Char
!
!
firstTo :: Int -> Maybe Int
firstTo n = find (x -> digitSum x == n) [1..]
GHCi> firstTo 27
Just 999
GHCi> firstTo 1
Just 1
GHCi> firstTo 13
Just 49

平奈井日�尺及穴永疋件弘
? 摩磁及方丹卅犯奈正毛㜳丹午五反�唗毛𠸎卞仄卅中
? 窣砑伉旦玄及平奈
? 瞰ㄩ丐月蛂垀卞掞井蛂氏匹中月井毛捼屯月
? 蛂垀匹靡ゴ毛𨈘坰仄凶中
? 仇及�及�
? 咡心及�(掞井及靡ゴ)毛睡日井及平奈(公及�及蛂垀)匹𨈘坰

窣砑伉旦玄及桶政
? 2勾及源楊互畿賡
? 矢失(正皿伙)及伉旦玄午仄化桶政
? [(※betty§, ※555-2938§), (※bonnie§, ※452-2928§), ＃]
? �倛卞軗𦷰允月斛猁衄
? Data.Map
? 詢厒卅𨈘坰互褫夔

矢失及伉旦玄匹桶政
? 迵尹日木凶平奈卞�仄化�毛𨈘坰允月憝杅
findKey :: (Eq k) => k -> [(k, v)] -> v
findKey key xs = snd . head . filter ((k, v) -> key == k) $ xs
GHCi> let phoneBook = [("betty", "555-2938"), ?
("bonnie", "452-2928"), ("patsy", "493-2928"), ("lucille", "205-2928"),
("wendy", "939-8282"), ("penny", "853-2492")]
GHCi> findKey "betty" phoneBook
"555-2938"
GHCi> findKey "bety" phoneBook
"*** Exception: Prelude.head: empty list

𨈘坰憝杅及蜊謎
? Maybe倰毛妏丹
findKey :: (Eq k) => k -> [(k, v)] -> Maybe v
findKey key [] = Nothing
findKey key ((k,v):xs)
| key == k = Just v
| otherwise = findKey key xs
? �心煋心毛蚚中凶桶政
findKey :: (Eq k) => k -> [(k, v)] -> Maybe v
findKey key xs = foldr
((k, v) acc -> if key == k then Just v else acc)
Nothing xs

灍俴瞰
Just "555-2938"
GHCi> findKey "penny" phoneBook
Just "853-2492"
Just "555-2938"
GHCi> findKey "wilma" phoneBook
Nothing
? 仇及?ndKey憝杅反Data.List及lookup憝杅午肮元

Data.Map
? 矢失及伉旦玄匹窣砑伉旦玄毛桶政允月午平奈卞�𡛟仄凶�互�勾井月引匹
允屯化及猁匼毛軗𦷰允月斛猁衄
? Data.Map乒斥亙奈伙卞詢厒卅窣砑伉旦玄互湔婓
? 仇仇井日反☆蟀砑伉旦玄毛妏丹★午晟丹測歹曰卞☆紼硃梯毛妏丹★午桶允

import
? Data.Map反Prelude支Data.List午�磁允月靡ゴ毛巨弁旦
禾奈玄仄化中月及匹党�葆五奶件禾奈玄允月
? import quali?ed Data.Map as Map
? 仇及import恅毛旦弁伉皿玄卞𤩸中化﹜?
公木井日公及旦弁伉皿玄毛GHCi匹伕奈玉

Data.Map及fromList憝杅
? 窣砑伉旦玄毛忳仃龰曰肮元�𡛟憝�S毛厥勾Map毛殿允
? 窣砑伉旦玄及方丹卞桶尨今木月互手反支窣砑伉旦玄匹反卅中
GHCi> Map.fromList [("betty", "555-2938"), ("bonnie", "452-2928"), ("patsy", "493-2928"),
("lucille", "205-2928"), ("wendy", "939-8282"), ("penny", "853-2492")]
Loading package array-0.5.0.0 ... linking ... done.
Loading package deepseq-1.3.0.2 ... linking ... done.
Loading package containers-0.5.5.1 ... linking ... done.
fromList [("betty","555-2938"),("bonnie","452-2928"),("lucille","205-2928"),
("patsy","493-2928"),("penny","853-2492"),("wendy","939-8282")]

杻釾
? 笭恚仄凶平奈互丐勻凶�磁﹜摽及幻丹及猁匼互妏歹木月
GHCi> Map.fromList [("MS",1),("MS",2),("MS",3)]
fromList [("MS",3)]
? 倰扑弘生民乓
? 平奈及倰弁仿旦互Ord匹丐曰�唗掀廌互斛猁
? 詢厒趙及猁秪
GHCi> :t Map.fromList
Map.fromList :: Ord k => [(k, a)] -> Map.Map k a

phoneBook及Map卞方月灍蚾
import qualified Data.Map as Map
!
phoneBook :: Map.Map String String
phoneBook = Map.fromList $ [("betty" , "555-2938"),
("bonnie" , "452-2928"),
("patsy" , "493-2928"),
("lucille", "205-2928"),
("wendy" , "939-8282"),
("penny" , "853-2492")]

Map.lookup卞方月𨈘坰
GHCi> :t Map.lookup
Map.lookup :: Ord k => k -> Map.Map k a -> Maybe a
GHCi> Map.lookup "betty" phoneBook
Just "555-2938"
GHCi> Map.lookup "wendy" phoneBook
Just "939-8282"
GHCi> Map.lookup "grace" phoneBook
Nothing

陔仄中楓瘍毛浲⻌仄化陔仄中Map毛釬月
GHCi> :t Map.insert
Map.insert :: Ord k => k -> a -> Map.Map k a -> Map.Map k a
GHCi> Map.lookup "grace" phoneBook
Nothing
GHCi> let newBook = Map.insert "grace" "341-9021" phoneBook
GHCi> Map.lookup "grace" newBook
Just "341-9021"

扔奶朮毛捼屯月
GHCi> :t Map.size
Map.size :: Map.Map k a -> Int
GHCi> Map.size phoneBook
6
GHCi> Map.size newBook
7

��楓瘍毛恅趼蹈匹反卅仁Int及伉旦玄午仄化桶政
? ※939-8282§匹反卅仁[9,3,9,8,2,8,2]午仄化桶政仄凶中互-互訄藹
? Data.Char及isDigit毛妏丹
GHCi> :t isDigit
isDigit :: Char -> Bool
GHCi> :t filter
filter :: (a -> Bool) -> [a] -> [a]
GHCi> :t digitToInt
digitToInt :: Char -> Int
import Data.Char
!
string2digits :: String -> [Int]
string2digits = map digitToInt . filter isDigit
GHCi> :t (filter isDigit)
(filter isDigit) :: [Char] -> [Char]
GHCi> :t (map digitToInt)
(map digitToInt) :: [Char] -> [Int]
GHCi> :t (map digitToInt) . (filter isDigit)
(map digitToInt) . (filter isDigit) :: [Char] -> [Int]
GHCi> string2digits "948-9282"
[9,4,8,9,2,8,2]

phoneBook毛string2digits匹穴永皿
GHCi> let intBook = Map.map string2digits phoneBook
GHCi> :t intBook
intBook :: Map.Map String [Int]
GHCi> Map.lookup "betty" intBook
Just [5,5,5,2,9,3,8]

��絝及��
? 平奈及笭恚互丐月午fromList反笭恚毛祅壺
? fromListWith毛妏丹
? 笭葩奀及淥月敃中毛樵戶日木月

Map.fromListWith
? 笭恚媆卞楓瘍毛磐磁
!
? 笭恚媆卞伉旦玄午仄化磐磁
!
? max匹郔湮�﹜(+)匹�及睿卅升毛龰月仇午手褫夔
phoneBookToMap :: (Ord k) => [(k, a)] -> Map.Map k [a]
phoneBookToMap xs = Map.fromListWith add xs
where add number1 number2 = number1 ++ ", " ++ number2
phoneBookToMap :: (Ord k) => [(k, a)] -> Map.Map k [a]
phoneBookToMap xs = Map.fromListWith
(++) $ map ((k, v) -> (k, [v])) xs

乒斥亙奈伙毛釬勻化心方丹
? 婬瞳蚚俶毛詢戶月凶戶卞乒斥亙奈伙卞煦仃月
? 乒斥亙奈伙井日反憝杅毛巨弁旦禾奈玄允月
? 乒斥亙奈伙毛奶件禾奈玄允月午?
公及乒斥亙奈伙互巨弁旦禾奈玄允月憝杅互瞳蚚褫夔
? 乒斥亙奈伙囀窒分仃匹妏尹月憝杅手隅膽褫夔

𢜔睡悝乒斥亙奈伙
? Geometory乒斥亙奈伙及釬傖
? Geometry.hs午中丹白央奶伙靡卞允月
? 珂螹匹乒斥亙奈伙靡毛硌隅
? module Geometry
? 公及棒卞巨弁旦禾奈玄允月憝杅靡毛蹈伃
? (sphereVolume, sphereArea, ＃, cuboidVolume) where
? 公及摽匹憝杅毛隅膽

蕆𦵴腔乒斥亙奈伙
? Geometry毛煦賃仄化蕾极及意�仍午卞煦賃
? Geometry午中丹犯奴伊弁玄伉毛釬傖
? 公及笢卞3勾及白央奶伙Sphere.hs, Cuboid.hs,
Cube.hs毛釬月
? Geometry犯奴伊弁玄伉及丐月犯奴伊弁玄伉奻及白央奶伙
井日import Geometry.Sphere卅升午import褫夔

端端舝

允仍中Haskell掂𤩸頗菴鞠梒逃桶揃蹋

Recommended

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to 允仍中Haskell掂𤩸頗菴鞠梒逃桶揃蹋 (20)

More from Hiromasa Ohashi (6)

允仍中Haskell掂𤩸頗菴鞠梒逃桶揃蹋

端端舝

允仍中Haskell掂𤩸頗 菴鞠梒 逃桶揃蹋

Recommended

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to 允仍中Haskell掂𤩸頗 菴鞠梒 逃桶揃蹋 (20)

More from Hiromasa Ohashi (6)

允仍中Haskell掂𤩸頗 菴鞠梒 逃桶揃蹋

允仍中Haskell掂𤩸頗菴鞠梒逃桶揃蹋

Similar to 允仍中Haskell掂𤩸頗菴鞠梒逃桶揃蹋 (20)

允仍中Haskell掂𤩸頗菴鞠梒逃桶揃蹋