arrayspowershelljagged-arrays

PowerShell array, loop first row

I have a problem with array as following with only one line:

$list = @()
$list =  (("ResourceGroup","Vm1"))


$list | ForEach-Object -Parallel {

    write-output $_[0] $_[1]

}

If I loop that array with one line, PowerShell prints the first 2 letter of each word. If I put 2 or more row like following:

    $list = @()
    $list =  (("ResourceGroup","Vm1"),`
              ("ResourceGroup","Vm2")
)

PowerShell print correctly the values inside.

There is a way to print correctly the value of an array with only one line?

Solution

  • ("ResourceGroup","Vm1") is interpreted as one array with two string elements, where as (("ResourceGroup","Vm1"), ("ResourceGroup","Vm2")) is interpreted as one array with 2 array elements, can be also called a jagged array. If you want to ensure that the first example is treated the same as the second example, you can use the comma operator ,:

    $list = , ("ResourceGroup","Vm1")
$list | ForEach-Object -Parallel {
    Write-Output $_[0] $_[1]
}

    To put it in perspective:

    $list = ("ResourceGroup","Vm1")
$list[0].GetType() # => String

$list = , ("ResourceGroup","Vm1")
$list[0].GetType() # => Object[]

    Write-Output with the -NoEnumerate switch combined with the Array subexpression operator @( ) can be another, more verbose, alternative:

    $list = @(Write-Output "ResourceGroup", "Vm1" -NoEnumerate)
$list | ForEach-Object -Parallel {
    Write-Output $_[0] $_[1]
}