How do I pass multiple parameters into a function

Question

If I have a function which accepts more than one string parameter, the first parameter seems to get all the data assigned to it, and remaining parameters are passed in as empty.

A quick test script:

Function Test([string]$arg1, [string]$arg2)
{
    Write-Host "`$arg1 value: $arg1"
    Write-Host "`$arg2 value: $arg2"
}

Test("ABC", "DEF")

The output generated is

$arg1 value: ABC DEF
$arg2 value: 

The correct output should be:

$arg1 value: ABC
$arg2 value: DEF

This seems to be consistent between v1 and v2 on multiple machines, so obviously, I'm doing something wrong. Can anyone point out exactly what?

Answer 1

Function Test([string]$arg1, [string]$arg2)
{
    Write-Host "`$arg1 value: $arg1"
    Write-Host "`$arg2 value: $arg2"
}

Test "ABC" "DEF"

Answer 2

The correct answer has already been provided but this issue seems prevalent enough to warrant some additional details for those wanting to understand the subtleties. I would have added this just as a comment but I wanted to include an illustration--I tore this off my quick reference chart on PowerShell functions. This assumes function f's signature is f($a, $b, $c):

Thus, one can call a function with space-separated positional parameters or order-independent named parameters. The other pitfalls reveal that you need to be cognizant of commas, parentheses, and white space.

For further reading see my article Down the Rabbit Hole: A Study in PowerShell Pipelines, Functions, and Parameters just published on Simple-Talk.com. The article contains a link to the quick reference/wall chart as well.

Answer 3

If you try:

PS > Test("ABC", "GHI") ("DEF")

you get:

$arg1 value: ABC GHI
$arg2 value: DEF

so you see that the parenthesis separates the parameters

If you try:

PS > $var = "C"
PS > Test ("AB" + $var) "DEF"

you get:

$arg1 value: ABC
$arg2 value: DEF

Now you could find some immediate usefulness of the parenthesis - a space will not become a separator for the next parameter - instead you have an eval function.

Answer 4

Function Test([string]$arg1, [string]$arg2)
{
    Write-Host "`$arg1 value: $arg1"
    Write-Host "`$arg2 value: $arg2"
}

Test("ABC") ("DEF")

Answer 5

I states the following earlier:

The common problem is using the singular form $arg, which is incorrect.
It should always be plural as $args.

The problem is not that.
In fact, $arg can be anything else. The problem was the use of the comma and the parantheses.
I run the following code that worked and the output follows:

Code:

Function Test([string]$var1, [string]$var2)
{
    Write-Host "`$var1 value: $var1"
    Write-Host "`$var2 value: $var2"
}

Test "ABC" "DEF"

Output:

$var1 value: ABC $var2 value: DEF

Answer 6

You call PowerShell functions without the parenthesis and without using the comma as a separator. Try using:

   test "ABC" "DEF"

In PowerShell the comma (,) is an array operator, e.g.

   $a = "one", "two", "three"

It sets $a to an array with three values.