performance - 这两种模式匹配中哪种方式更受欢迎？

Question

我只是好奇，这两个函数会做同样的事情。但是我应该使用哪一个？

let f a =
    match a with
        b -> a;; 
let f a =
    match a with
        b -> b;;

还是仅取决于您的喜好？
我觉得第二个会更好，但我不确定。

Answer 1

Performance wise there is no difference. Style-wise b -> a is a bit problematic because you have an unused variable b. _ -> a would make more sense. Other than that, it's just preference.

Personally I would prefer _ -> a over b -> b because it doesn't introduce an extra variable.

PS: I assume in your real code there are more cases than just b - otherwise you could just write let f a = a.

Answer 2

另外，在您的特定示例中，我将使用function

let f = function
      | b -> b