F#:检查值是字符串数组，字符串数组还是字符串 [英] F#: check if a value is an array of strings, an array of arrays of string or a string

问题描述

我需要使用match来检查值是字符串数组还是字符串.我尝试了一些徒劳的事情

I need use match to check if a value is an array of strings or a string. I've tried something in the vain of

| :? string[] -> ..
| :? string -> ..
| :? array<string[]> -> ..

但无济于事.

有帮助吗?

推荐答案

您需要稍微修改语法，但是您几乎是正确的

You need to modify the syntax slightly, but you were almost correct

let fn (arg:obj) = 
    match arg with
    | :? string as str -> printfn "string"
    | :? (string[]) as arr -> printfn "string array"

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