小编Tob*_*rdt的帖子

只想澄清这是我编程的第一天,我意识到这个问题是多么愚蠢:D

1)为什么不起作用？

ghci>''hello'' ++ ''world''

<interactive>:40:1: error
    * Syntax error on ''hello''
      Perhaps you intended to use TemplateHaskell or TemplateHaskellQuotes
    * In the Template Haskell quotation ''hello''

ghci>''hello'' ++ '' '' ++ ''world''

<interactive>:41:17: error: parse error on input '''

我应该在texteditor中添加一些内容以使其正常工作吗？或者我只是做了一些菜鸟错误？

2)

ghci> ''Steve'' !! 2

<interactive>:42:2: error
    * Syntax error on ''Steve''
      Perhaps you intended to use TemplateHaskell or TemplateHaskellQuotes
    * In the Template Haskell quotation ''Steve''
ghci>[1,2,3,5,8] !! 2
3

当我使用数字执行这些命令时,它可以工作,但不能使用字符.我一定做错了什么,但我不确定是什么:/

提前致谢!

完成以下函数定义:

    -- maxi x y returns the maximum of x and y

我应该在不使用Haskell中的'maximum'函数的情况下完成此任务.

maxi :: Integer -> Integer -> Integer
maxi x y
 |x > y = x
 |y > x = y 

然后我不明白该怎么做.如何测试代码是否有效？它看起来有点正确吗？

我正在尝试在Haskell中创建一个代码,当k是偶数时,n ^ k =(n*n)^(k/2),如果k,则n ^ k = n*(n ^(k-1))很奇怪.我做错了什么,但我无法弄清楚如何解决它.

power2 :: Integer -> Integer -> Integer 
power2 n 0 = 1
power2 n k
   | k < 0 = error "negative argument"
   | k `mod` 2 == 0 = even            -- Am I supposed to write  = even here?
   | otherwise = odd
if k even = (n 2) ( div k 2)       -- (n^2)^(k/2)  ???
if k odd = n * (n) (k-1))          -- Is this n^(k-1) ???

我对Haskell(和编程)很陌生.我的任务是定义一个功能,返回一整套卡(又名52卡).试图将我的思维过程包含在代码旁边的注释中.

- 我定义的值

data Suit = Club | Diamond | Heart | Spade  deriving (Show, Enum)

data Value = Two | Three | Four | Five | Six | Seven
          | Eight | Nine | Ten | Jack | Queen
          | King | Ace  deriving (Show, Enum) 

type Card = (Suit, Value)  -- A card must have a suit and a value
type Deck = [Card]        -- A deck consists of a list of cards

fullDeck :: Deck    -- My …