Finds the nth index of a char in a string.

Find-NthIndexOf.ps1

<#
.SYNOPSIS
    Finds the nth index of a char in a string.
.DESCRIPTION
    Finds the nth index of a char in a string, returns -1 if the char does not exist, or if nth is out of range.
.INPUTS
    System.Char.
    System.String.
    System.Int.
.OUTPUTS
    System.Int.
.PARAMETER Target
    The string to evaluate.
.PARAMETER Value
    The char to locate.
.PARAMETER Nth
    the occurance of the char to find.
.EXAMPLE
    PS C:\> Find-NthIndexOf -Target "CN=me,OU=Users,DC=domain,DC=org" -Value "=" -Nth 2
    8
.EXAMPLE
    PS C:\> ($dn = "CN=me,OU=Users,DC=domain,DC=org").SubString((Find-NthIndexOf -Target $dn -Value "=" -Nth 2) - 2)
    OU=Users,DC=domain,DC=org
.NOTES
    Returns -1 if the char does not exist, or if nth is out of range.
.LINK
    http://stackoverflow.com/questions/186653/c-sharp-indexof-the-nth-occurrence-of-a-string
.LINK
    https://dotps1.github.io
#>

Function Find-NthIndexOf {

    [CmdletBinding()]
    [OutputType(
        [Int]
    )]

    Param (
        [Parameter(
            Mandatory = $true,
            ValueFromPipeline = $true,
            ValueFromPipelineByPropertyName = $true
        )]
        [String[]]
        $Target,

        [Parameter(
            Mandatory = $true,
            ValueFromPipelineByPropertyName = $true
        )]
        [Char]
        $Value,

        [Parameter(
            ValueFromPipelineByPropertyName = $true
        )]
        [Int]
        $Nth = 1
    )

    Process {
        foreach ($item in $Target) {
            $Value = [Regex]::Escape(
                $Value
            )

            $match = [Regex]::Match(
                $item, "(($Value).*?){$Nth}" 
            )

            if ($match.Success) {
                Write-Output -InputObject $match.Groups[2].Captures[$Nth - 1].Index
            } else {
                Write-Output -InputObject -1
            }
        }
    }
}