Array.Find on powershell 阵列 [英] Array.Find on powershell array

问题描述

如何使用 Array.Find 方法在 PowerShell 中?

例如:

$a = 1,2,3,4,5[数组]::Find($a, { args[0] -eq 3 })

给予

找不到Find"和参数计数的重载:2".在行:3 字符:1+ [数组]::Find($a, { $args[0] -eq 3 })+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+ CategoryInfo : NotSpecified: (:) [], MethodException+ FullQualifiedErrorId : MethodCountCouldNotFindBest

数组类具有我期望的方法，如下所示:

PS>[阵列] |获取成员 - 静态类型名称:System.Array名称 MemberType 定义---- ---------- ----------Find 方法 static T Find[T](T[] 数组，System.Predicate[T] 匹配)

是否应该将数组强制转换为其他内容以匹配 T[] 类型?我知道还有其他方法可以实现查找功能，但我想知道为什么这不起作用.

解决方案

您需要将 ScriptBlock 转换为 Predicate[T].考虑以下示例:

[Array]::Find(@(1,2,3), [Predicate[int]]{ $args[0] -eq 1 })# 结果:1

您收到错误的原因是没有匹配的方法重载，在您传入 PowerShell ScriptBlock 的情况下.正如您在 Get-Member 输出中所指出的，没有接受 ScriptBlock 作为第二个参数的 Find() 方法重载.>

[Array]::Find(@(1,2,3), { $args[0] -eq 1 })

<块引用>

找不到Find"和参数计数的重载:2".在行:1 字符:17+ [数组]::Find(@(1,2,3), { $_ -eq 1 })+ ~~~~~+ CategoryInfo : NotSpecified: (:) [], MethodException+ FullQualifiedErrorId : MethodCountCouldNotFindBest

How can I use the Array.Find method in powershell?

For example:

$a = 1,2,3,4,5
[Array]::Find($a, { args[0] -eq 3 })

gives

Cannot find an overload for "Find" and the argument count: "2".
At line:3 char:1
+ [Array]::Find($a, { $args[0] -eq 3 })
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodException
    + FullyQualifiedErrorId : MethodCountCouldNotFindBest

The array class has the methods I expect, as given by:

PS> [Array] | Get-Member -Static

   TypeName: System.Array

Name            MemberType Definition                                                                                       
----            ---------- ----------
Find            Method     static T Find[T](T[] array, System.Predicate[T] match)

Should the array be casted to something else to match the T[] type? I know there are other ways to achieve the find functionality, but I was wondering why this doesn't work.

解决方案

You need to cast the ScriptBlock as a Predicate[T]. Consider the following example:

[Array]::Find(@(1,2,3), [Predicate[int]]{ $args[0] -eq 1 })
# Result: 1

The reason that you received the error, is because there was no matching method overload, in the case where you're passing in a PowerShell ScriptBlock. As you noted in your Get-Member output, there is no Find() method overload that accepts a ScriptBlock as its second parameter.

[Array]::Find(@(1,2,3), { $args[0] -eq 1 })

Cannot find an overload for "Find" and the argument count: "2". At line:1 char:17 + [Array]::Find(@(1,2,3), { $_ -eq 1 }) + ~~~~~ + CategoryInfo : NotSpecified: (:) [], MethodException + FullyQualifiedErrorId : MethodCountCouldNotFindBest

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