使用 F# 计算数字列表的笛卡尔积 [英] Calculating the Cartesian product of a list of numbers with F#

问题描述

我是 f# 的新手

我正在尝试计算数字列表的笛卡尔积.我借"了这个.

I am try to calculate the Cartesian products of a list of numbers. I "borrowed" this.

let xs = [1..99]
let ys = [1..99]
seq {for x in xs do for y in ys do yield x * y}

有没有更好或更优雅的方法?

Is there a better or more elegant way?

加里

推荐答案

基于 List 模块提供的功能解决该问题的另一种可能性是:

Another possibiltiy to tackle the problem based on functionality provided by the List module would be:

let xs = [1..99]
let ys = [1..99]
let zs = xs |> List.collect (fun x -> ys |> List.map (fun y -> x*y))

这避免了对 .concat 的额外调用，也应该完成这项工作.

which avoids the extra calls to .concat and should also do the job.

但我会坚持你的解决方案.它应该是最易读的，这是真正的比赛赢家.(试着大声朗读代码.你的完全可以理解，而诺多灵或我的则不是.)

But I'd stick with your solution. It should be the most readable which is a real matchwinner. (Just try to read the codes out loud. Yours is perfectly understandable and Noldorins or mine are not.)

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