F#等同于C#中的is关键字? [英] F# equivalent of `is` keyword in C#?

问题描述

我在F#的第一天.如果我有这个话:

let cat = Animal()

现在我该如何在以后检查cat is Animal?

在C#中

bool b = cat is Animal;

在F#中?

解决方案

@ildjarn在此功劳第一，但我在这里提交了答案，因此可以接受.

C#is关键字的F#等效项是:?.例如:

let cat = Animal()
if cat :? Animal then
    printfn "cat is an animal."
else
    printfn "cat is not an animal."

My first F# day. If I have this:

let cat = Animal()

Now how do I check at later stage if cat is Animal?

In C#

bool b = cat is Animal;

In F#?

解决方案

@ildjarn deserves the credit here for answering first, but I'm submitting the answer here so it can be accepted.

The F# equivalent of the C# is keyword is :?. For example:

let cat = Animal()
if cat :? Animal then
    printfn "cat is an animal."
else
    printfn "cat is not an animal."

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