CODEWITHSUNDEEP
powershellparameter-passing
Jonathan
Jonathan

Reputation: 7561

How to keep parameter list in a variable

I have a script internal.ps1 which accepts certain params:

param ($paramA, $paramB)
Write-Host $PSBoundParameters

And a script caller.ps1 that calls it:

.\internal -paramA A -paramB B

It works great:

PS C:\temp> .\caller
[paramA, A] [paramB, B]    <<<< bounded to both params

However, in caller I want to keep the parameters to internal in a var, and use it later. However, that doesn't work:

$parms = "-paramA A -paramB B"
# Later...
.\internal $parms

Result: [paramA, A -paramB B]   <<<<< All got bounded to ParamA

Neither does using an array:

$parms = @("A", "B")
# Later...
.\internal $parms

Result: [paramA, System.Object[]]  <<<< Again, all bound to ParamA

How can I accomplish this? Note that the actual commandline is more complex, and may have unknown length.

Upvotes: 4

Views: 1554

Answers (3)

Michael Sorens
Michael Sorens

Reputation: 36738

The splatting operator (@) should do what you need. Consider first this simple function:

function foo($a, $b) { "===> $a + $b" }

Calling with explicit arguments yields what you would expect:

foo "hello" "world"
===> hello + world

Now put those two values in an array; passing the normal array yields incorrect results, as you have observed:

$myParams = "hello", "world"
foo $myParams
===> hello world +

But splat the array instead and you get the desired result:

foo @myParams
===> hello + world

This works for scripts as well as for functions. Going back to your script, here is the result:

 .\internal @myParams
[paramA, hello] [paramB, world]

Finally, this will work for an arbitrary number of parameters, so know a priori knowledge of them is needed.

Upvotes: 5

Ansgar Wiechers
Ansgar Wiechers

Reputation: 200373

Your script expects 2 arguments, but your previous attempts pass just a single one (a string and an array respectively). Do it like this:

$parms = "A", "B"
#...
.\internal.ps1 $parm[0] $parm[1]

Upvotes: 0

Lo&#239;c MICHEL
Lo&#239;c MICHEL

Reputation: 26170

powershell -file c:\temp\test.ps1 @("A","B")

or

powershell -command "c:\temp\test.ps1" A,B

Upvotes: 0

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