Haskell函数返回值

Question

有什么区别

dotEx1 = map(+3) . filter (>100)

和

dotEx1 xs = map(+3) . filter (>100) xs

以来

myFilter xs = filter (>100) xs 

和

myFilter = filter (>100) 

是不一样的原因

dotEx1 = map(+3) . filter (>100)

和

dotEx1 xs = map(+3) . filter (>100) xs

相同？

Answer 1

该.函数定义如下:

(.) :: (b -> c) -> (a -> b) -> a -> c

由.运算符组成的函数必须接受一个参数.因此,

dotEx1 = map(+3) . filter (>100)

是相同的

dotEx1 xs = (map(+3) . filter (>100)) xs