Return variable from one function to another in powershell

Question

I am inside function #1 and triggering function #2. Function #2 has a variable that I want to get back into function #1 and use it.

My output ends up being:

hey there
var is:

What I want is the output to be:

var is: hey there

Why is it that I can feed a function a variable, and it uses it, but when I change that variable in the #2 function, it does not change the variable after it returns?

$var = $null

function one() {

two($var)

write-host "var is:" $var

}


function two($var){

$var = "hey there"

return($var)

}

clear
one

@DanielMann if I type "return($var)", it only outputs $var, it does not change the variable when it actually returns. — Aaron
– Aaron, Commented Oct 3, 2019 at 14:41
@Aaron variables in powershell are locally scoped, meaning that changing the value of a variable with the name var inside two won't change the value of var inside the calling scope — Mathias R. Jessen
– Mathias R. Jessen, Commented Oct 3, 2019 at 14:50

Mathias R. Jessen · Accepted Answer · 2019-10-03 14:44:17Z

1

First, change your two function to actually return a value:

function two {
  $var = "hey there"

  return $var
}

and then update the one function to actually "capture" the output value by assigning it to a variable:

function one {
  # PowerShell doesn't use parentheses when calling functions
  $var = two

  Write-Host "var is:" $var
}

answered Oct 3, 2019 at 14:44

Mathias R. Jessen

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3 Comments

Aaron Over a year ago

Is there a way to do this if you call another function and that function has 2 or more variables in it? I know you set $var = two , so say function two has 2 variables in it, how do you get them back?

Mathias R. Jessen Over a year ago

$var1,$var2 = two

Mathias R. Jessen Over a year ago

@Aaron Might be worth reading this document as well - in PowerShell you don't need to specify the return keyword in order to pass data back to the caller (which may be slightly confusing at first)

PreventRage · Accepted Answer · 2022-04-21 13:54:50Z

0

If you really do want to reach up and change a variable in the scope of your caller, you can...

Set-Variable -Name $Name -Value $Value -Scope 1

It's a little meta/quirky but I've run into cases where it seemed proper. For example, I once wrote a function called RestoreState that I called at the beginning of several functions exported from a module to handle some messy reentrant cases; one of the things it did is reach up and set or clear $Verbose in the calling function's scope.

answered Apr 21, 2022 at 13:54

PreventRage

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