难以理解 Powershell 工作流程 ForEach

Question

我正在尝试使用 Powershell Workflows 和一些我需要并行完成的工作。

我没走多远就遇到了我的第一个障碍，但我不明白我做错了什么：

$operations = ,("Item0", "Item1")

ForEach ($operation in $operations) {
    Write-Output "Item0: $($operation.Item(0)) Item1: $($operation.Item(1))"
}

workflow operationsWorkflow{
    Write-Output "Running Workflow"
    $operations = ,("Item0", "Item1")
    ForEach -Parallel ($operation in  $operations) {
        #Fails: Method invocation failed because [System.String] does not contain a method named 'Item'.
        #Write-Output "Item0: $($operation.Item(0)) Item1: $($operation.Item(1))"

        Write-Output "Item $operation"
    }
}

operationsWorkflow

Answer 1

问题已解决，感谢this excellent article on powershell arrays

Now, since it’s already an array, casting it again doesn’t result in a second level of nesting:

PS (66) > $a = [array] [array] 1

PS (67) > $a[0]

1

However using 2 commas does nest the array since it is the array construction operation:

PS (68) > $a = ,,1

PS (69) > $a[0][0]

1

鉴于此，这工作正常：

workflow operationsWorkflow{
    Write-Output "Running Workflow"
    $operations = ,,("Item0", "Item1")
    ForEach -Parallel ($operation in  $operations) {
            Write-Output "Item0: $($operation.Item(0)) Item1: $($operation.Item(1))"
    }
}

operationsWorkflow

但是，如果在工作流之外添加第二个逗号，则会出现错误。所以这是 workflow 或 parallel 特定问题和解决方法。

难以理解 Powershell 工作流程 ForEach

Trouble Understanding Powershell Workflow ForEach

powershell

powershell-workflow