How can I put my Invoke-Command results in a comma-delimited string

PowerShell 5.1

How can I get the results of Invoke-Command into a comma-delimited string

Invoke-Command -ComputerName $manyComputers -Credential $credential -ScriptBlock {
   hostname
}  

expected output:

"server1,server2"

>Solution :

Use -join in Windows PowerShell 5.1:

$result = (Invoke-Command -ComputerName $manyComputers -Credential $credential -ScriptBlock {
    $env:COMPUTERNAME
}) -join ','

In PowerShell 7+ you can use Join-String, much nicer syntax:

$result = Invoke-Command -ComputerName $manyComputers -Credential $credential -ScriptBlock {
    $env:COMPUTERNAME
} | Join-String -Separator ','