A missing Windows PowerShell function.

Join-String.ps1

function Join-String {
	[CmdletBinding()]
	param (
		[Parameter(ValueFromPipeline)]$Inputobject,
		[string]$Property, [string]$Separator='', 
		[string]$OutputPrefix, [string]$OutputSuffix,
		[switch]$SingleQuote, [switch]$DouleQuote,
		[string]$FormatString
	)
	begin {
		$content = [System.Collections.Generic.List[object]]::new()
	}
	process {
		if ($Inputobject) {
			if ($Property) {$content.AddRange(@($Inputobject.$Property))}
			else {$content.AddRange(@($Inputobject))}
		}
	}
	end {
		if (-not $content.count) {return}
		$q = if ($DouleQuote) {'"'} elseif ($SingleQuote) {"'"} else {''}
		$r = $(foreach ($p in $content) {
			if ($p -or $p -eq 0) {
				if ($FormatString) {$p = $FormatString -f $p}
				"$q$p$q"
			}
		}) -join $Separator
		if ($OutputPrefix) {$r = "$OutputPrefix$r"}
		if ($OutputSuffix) {$r = "$r$OutputSuffix"}
		$r
	}
} # END Join-String