【发布时间】：2022-06-13 21:22:47
【问题描述】：
在这段代码中 sumDaytime 不起作用，我不知道问题所在。
data Temperature = Night Double | Daytime Double deriving (Eq,Show)
isDaytime :: Temperature -> Bool
isDaytime (Daytime y) = True
isDaytime (Night y) = False
countDaytime :: [Temperature] -> Double
countDaytime [] = 0.0
countDaytime (x:xs)
| (isDaytime x) = 1.0 + (countDaytime xs)
| otherwise = countDaytime xs
sumDaytime :: [Temperature] -> Double
sumDaytime [] = 0.0
sumDaytime (x:xs)
| (isDaytime x) = x + (sumDaytime xs)
| otherwise = sumDaytime xs
daytimeAvg :: [Temperature] -> Double
daytimeAvg [] = 0.0
daytimeAvg x = sumDaytime x `div` countDaytime x
Example:
daytimeAvg [Night (-5), Night (-6), Daytime 0, Daytime 3, Daytime 5, Daytime 1, Night (-7)] == 2.25
daytimeAvg [Night 5, Night 0, Daytime 1, Daytime 10, Daytime 8, Daytime 5, Night 2] == 6.0
此代码有效，但它仅适用于一个字符，而不适用于字符串中的所有字符。
snakeToCamel :: String -> String
snakeToCamel "" = ""
snakeToCamel (x:x1:xs)
| x == '_' = toUpper x1 : snakeToCamel xs
| otherwise = x:x1: snakeToCamel xs
Example:
snakeToCamel "apple" == "apple"
snakeToCamel "snake_to_camel" == "snakeToCamel"
snakeToCamel "snake_2_camel" == "snake2Camel"
snakeToCamel "i_am_in_snake_case" == "iAmInSnakeCase"
我不知道我的代码有什么问题。
match :: String -> String -> Maybe Char
match (x:xs) (y:ys)
| ' ' == y = Nothing
| x /= y = Just x
| x == y = match xs ys
| otherwise = Nothing
Example:
match "alma" "alma" == Nothing
match "alma" "asztal" == Just 'l'
match "asztal" "alma" == Just 's'
match "" "" == Nothing
【问题讨论】：
-
请比“不工作，我不知道问题”更具体。它以什么方式不起作用？它不编译吗？如果是这样，您是否收到可以与我们分享的错误？您是否得到了意想不到的结果，如果是，您期望得到什么结果？
标签： haskell