PowerShell/CLI: "Foreach" loop with multiple arrays

Question

I have a PowerCLI script that powers off a VM, changes its memory and cpu, and then powers it back on. I've adapted the script to utilize variables. This all works perfectly.

I'm now trying to modify the script to utilize arrays, in order to cycle through numerous VMs. The script portions that powers off and powers on the VMs works perfectly.

The trouble I'm having is using variables from two arrays in a foreach loop.

For each VM in $vm_name, I need to set the corresponding amount of memory found in $memory_gb.

This is what I have (it currently sets the same amount of memory ("1") for all of the VMs)....

$vm_name = @("OMAC-SBXWIN7AJM", "OMAC-SBXWIN2012R2AJM", "OMAC-SBXWIN2008R2AJM")
$memory_gb = 2,4,4

# SET THE VM MEMORY
Write-Host 'NOW SETTING THE VM MEMORY'
foreach ($objItem in $vm_name)
{Set-VM -VM $vm_name -MemoryGB 1 -confirm:$false 
Break
}

https://i.stack.imgur.com/E9hfY.png

...I've tried nesting a second foreach loop inside of the first, to no avail.

How do write the script so each VM in $vm_name, gets the corresponding amount of memory found in $memory_gb?

TheMadTechnician · Accepted Answer · 2014-08-08T15:32:58.073

6

You have 2 options. First (and not what I would suggest) is a For() loop. It would go something like this:

For($I=0;$I -lt $vm_name.count;$I++){
    Set-VM -VM $vm_name[$I] -MemoryGB $memory_gb[$I] -confirm:$false
}

The better way would be to put it in a CSV with headers like VMName, Memory and then list each VM and the memory you want in it. Then run something like:

Import-CSV C:\Path\To\File.CSV | ForEach{Set-VM -VM $_.VMName -MemoryGB $_.memory -confirm:$false}

edited Aug 08 '14 at 15:32

answered Aug 07 '14 at 20:57

TheMadTechnician

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Putting it into a data file is quite clever, hats off. – JensG Aug 07 '14 at 20:59
This worked perfectly. Thank you! I will certainly be using a .CSV, as Ill eventually be modifying numerous machines. – James McCallister Aug 08 '14 at 15:08
This worked, but I got this error.... Set-VM : Cannot bind parameter 'MemoryGB' to the target. Exception setting "MemoryGB": "Object reference not set to an instance of an object." At U:\How To\PowerCLI\Test.ps1:8 char:36 + Set-VM -VM $vm_name[$i] -MemoryGB $memory_gb[$i] -confirm:$false + ~~~~~~~~~~~~~~ + CategoryInfo : WriteError: (:) [Set-VM], ParameterBindingExcept ion + FullyQualifiedErrorId : ParameterBindingFailed,VMware.VimAutomation.ViCo re.Cmdlets.Commands.SetVM Since it worked, does the error really matter? – James McCallister Aug 08 '14 at 15:19
That's probably because I used -le instead of -lt so it was trying to iterate a 4th VM/memory set. I really expected you to utilize the second option, so I didn't pay as close of attention as I should have on the first one. I'll update the answer shortly to rectify that. – TheMadTechnician Aug 08 '14 at 15:32

score 6 · Answer 2 · answered Jan 12 '15 at 17:19

6

You can use Zip function:

function Zip($a1, $a2) {
    while ($a1) {
        $x, $a1 = $a1
        $y, $a2 = $a2
        [tuple]::Create($x, $y)
    }
}

Usage:

zip 'a','b','c' 1,2,3 |% {$_.item1 + $_.item2}

Result:

a1
b2
c3

answered Jan 12 '15 at 17:19

Mark Toman

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@js2010 to clear it up for future readers: the `$x, $a1 = $a1` syntax is unpacking the next member of the array instead of keeping a manual iterator `$i` or similar – Maximilian Burszley Apr 12 '21 at 03:06

score 3 · Answer 3 · answered Aug 08 '14 at 09:04

3

Another, more compact, solution is to use a hashtable:

$vms = @{"OMAC-SBXWIN7AJM" = 2; "OMAC-SBXWIN2012R2AJM" = 4; "OMAC-SBXWIN2008R2AJM" = 4}

# SET THE VM MEMORY
Write-Host 'NOW SETTING THE VM MEMORY'
foreach ($vm in $vms.getEnumerator()){
    Set-VM -VM $vm.Name -MemoryGB $vm.Value -confirm:$false 
}

answered Aug 08 '14 at 09:04

Raf

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This also worked for me. Thanks! I hadnt considered uses a hash table. – James McCallister Aug 08 '14 at 15:09

thepi · Answer 4 · 2019-02-06T05:37:18.167

3

$vm_name = @("OMAC-SBXWIN7AJM", "OMAC-SBXWIN2012R2AJM", "OMAC-
SBXWIN2008R2AJM")
$memory_gb = 2,4,4

# SET THE VM MEMORY
Write-Host 'NOW SETTING THE VM MEMORY'
foreach ($objItem in $vm_name)
{
    Set-VM -VM $vm_name -MemoryGB $memory_gb[$vm_name.indexOf($objItem)] -confirm:$false 
    Break
}

This will work as long as the two arrays are the same size.

edited Feb 06 '19 at 05:37

answered Nov 22 '17 at 21:50

thepi

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2
12

1

you sir are a gentleman and a scholar, i could not figure out how to pass two array type variables to a foreach loop without it doing each array item on the other array items each time. so something that should have ran 4 loops was doing 16. But this part saved me: [$vm_name.indexof($objItem)] – moore1emu Oct 25 '18 at 19:13
Index of is a pretty clever solution. – nethero Dec 03 '19 at 14:03

score 1 · Answer 5 · answered Aug 07 '14 at 20:57

1

$vm_name = @("OMAC-SBXWIN7AJM", "OMAC-SBXWIN2012R2AJM", "OMAC-SBXWIN2008R2AJM")
$memory_gb = (2,4,4)

# SET THE VM MEMORY
Write-Host 'NOW SETTING THE VM MEMORY'
for( $i = 0; $i -lt $vm_name.length; $i++) {
  $vm = $vm_name[$i]
  $gb = $memory_gb[$i]
  write-host setting $vm to $gb GB ...
  Set-VM -VM $vm -MemoryGB $gb -confirm:$false 
}

You just need to ensure both arrays are of the same length.

answered Aug 07 '14 at 20:57

JensG

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@JamesMcCallister: I'm flattered, but on SO thanks is usually expressed in upvotes and/or accepting the best answer :-) – JensG Aug 08 '14 at 17:11

PowerShell/CLI: "Foreach" loop with multiple arrays

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