Powershell Array to string with specific formatting - arrays

Question

Suppose I have an array with random values in it, like for instance
$a=#(0..5)
and I would like to format that array in a string like this :
{0,1,2,3,4}
comma separated values between curly braces. The "catch" is that I don't know in advance the size of the array, and in some cases, when there's only one record the type won't be array but psobject, when it's a unique PSObject I don't need curly braces and commas, I want to leave it as it is.
Thanks!

Answer 1

I would go for this (if statement on the input object type, and use of #beatcracker's method) :
Code :
//insert an array and a custom object in an input array
$input = #(#(0, 1, 2, 3, 4, 5),
[PSCustomObject]#{ title = "My"; first = "Custom"; last = "Object" })
//an empty output array
$output = #()
//foreach item in the input array
foreach($item in $input) {
//if item base type is array
if($item.GetType().BaseType.Name -eq "Array") {
//process and add to output array
$output += "{{{0}}}" -f ($item -join ",")
} else {
//add to output array as-is
$output += $item
}
}
//echo output array
$output
Output :
{0,1,2,3,4,5}
title first last
----- ----- ----
My Custom Object
Info : {0} is a placeholder for the 1st value after -f, ($item -join ",") ; the next one would have been {1} (more info here).
Additional curly brackets are there to escape surrounding curly brackets to make sure they appear in the final string.