How do I convert an array object to a string in PowerShell?

Question

How can I convert an array object to string?

I tried:

$a = \"This\", \"Is\", \"a\", \"cat\"
[system.String]::J         


        

Answer 1

1> $a = "This", "Is", "a", "cat"

2> [system.String]::Join(" ", $a)

Line two performs the operation and outputs to host, but does not modify $a:

3> $a = [system.String]::Join(" ", $a)

4> $a

This Is a cat

5> $a.Count

1