我如何将Haskell翻译成F＃？ [英] how do i translate this Haskell to F#?

问题描述

我试图通过翻译一些很久以前我写的Haskell代码来学习F＃，但我被卡住了！

I'm trying to learn F# by translating some Haskell code I wrote a very long time ago, but I'm stuck!

percent       :: Int -> Int -> Float
percent a b    = (fromInt a / fromInt b) * 100

freqs         :: String -> [Float]
freqs ws       = [percent (count x ws) (lowers ws) | x <- ['a' .. 'z']]

let percent a b = (float a / float b) * 100.

虽然我不喜欢必须拥有。 100美元以后。

although i dont like having to have the . after the 100.

我在 freqs 中执行的操作的名称是什么，以及如何翻译它到F＃？

What is the name of the operation I am performing in freqs, and how do I translate it to F#?

编辑： count 和降低是 Char - >字符串 - > Int 和字符串 - > Int 分别和我已经翻译过这些。

count and lowers are Char -> String -> Int and String -> Int respectively, and I have translated these already.

谢谢

推荐答案

这是一个列表理解，在F＃中它看起来像下面的最后两行：

This is a list comprehension, and in F# it looks like the last two lines below:

// stub out since dunno implementation
let count (c:char) (s:string) = 4
let lowers (s:string) = 10
// your code
let percent a b = (float a / float b) * 100.
let freq ws = [for x in ['a'..'z'] do 
                   yield percent (count x ws) (lowers ws)]

更一般地说，我认为Haskell列表解析具有以下示例所建议的形式，显示相应的F＃。

More generally I think Haskell list comprehensions have the form suggested by the example below, and the corresponding F# is shown.

// Haskell
// [e(x,y) | x <- l1, y <- l2, pred(x,y)]
// F#
[for x in l1 do
    for y in l2 do
        if pred(x,y) then
            yield e(x,y)]

这篇关于我如何将Haskell翻译成F＃？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！