How do I use validatepattern for multiple integers?

November 29, 2021

Basically, I need to use validate pattern to validate a few numbers. I need to be able to run .\Myfilename "number" "number" "number" "number" "number" and it should do a few things with those numbers in the script.

An actually example of what I would type is: .\Myfilename 100 100 20 30 50

What I can’t figure out is how to use validatepattern to assure these numbers are integers.

This is what I tried:

Param ([ValidatePattern("\d")] $G1 = 0, $G2= 0, $G3 = 0, $G4 = 0, $G5 = 0)

I also tried:

Param ([ValidatePattern("\d\s\d\s\d\s\d\s\d")] $G1 = 0, $G2= 0, $G3 = 0, $G4 = 0, $G5 = 0)

To no avail… Any help would be appreciated!

>Solution :

I don’t believe a ValidatePattern Attribute is needed in this case, unless there actually is a specific pattern you want the arguments to have. In addition, you don’t need to have one parameter per argument. You can have only one parameter and type constraint it to [int[]] and have the parameter as ValueFromRemainingArguments argument to make sure you’re capturing all inputs.

Sample script.ps1:

[cmdletbinding()]
param(
    [parameter(ValueFromRemainingArguments)]
    [int[]]$Numbers
)

$i = 0

foreach($number in $Numbers)
{
    [pscustomobject]@{
        ArgumentNumber = ($i++)
        Input = $Number
        IsInt = $Number -is [int]
    }
}

Sample Input and Output:

PS /> ./script.ps1 123 345 567           

ArgumentNumber Input IsInt
-------------- ----- -----
             0   123  True
             1   345  True
             2   567  True

And if you were to use an invalid input such as a string:

PS /> ./script.ps1 123 345 567 'asd'

$Error[0].Exception.InnerException.Message would be:

Cannot convert value "System.Collections.Generic.List`1[System.Object]" to type "System.Int32[]". Error: "Cannot convert value "asd" to type "System.Int32". Error: "Input string was not in a correct format.""

Side note, using this method the input should always follow one of the following formats:

<int><white space><int><white space><int><white space>
<int><comma><int><comma><int><comma>

An input that does not follow this syntax will get you an exception.

<int><comma><int><white space><int>, i.e.: 123, 345 567

Will get you the following exception:

Cannot convert value "System.Collections.Generic.List`1[System.Object]" to type "System.Int32[]". Error: "Cannot convert the "System.Object[]" value of type "System.Object[]" to type "System.Int32"."