Why PowerShell consider @() syntax differently

Question

Array initialization works differently in powershell

$scripts = @(
    ("01", "a" , "01_Cleanup")
    ,("02", "b" , "02_Cleanup")
);

Output:

$scripts[0] - "01"
$scripts[1] - "a"
$scripts[2] - "01_Cleanup"
$scripts[3] - "02"
"b"
"02_Cleanup"

---

Please notice "," in array initialization.:

$scripts = @(
    ("01", "a" , "01_Cleanup"),
    ("02", "b" , "02_Cleanup")
);

Output:

$scripts[0] - "01"
"a"
"01_Cleanup"
$scripts[1] - "02"
"b"
"02_Cleanup"

Why?

Answer 1

Its because of different usage of the Comma operator (binary vs unary):

As a binary operator, the comma creates an array. As a unary operator, the comma creates an array with one member. Place the comma before the member.

---

Binary:

@(
    ("01", "a" , "01_Cleanup"),
    ("02", "b" , "02_Cleanup")
) | foreach { Write-Host $_};

Output:

01 a 01_Cleanup
02 b 02_Cleanup

---

Unary:

 @(
    ("01", "a" , "01_Cleanup")
    ,("02", "b" , "02_Cleanup")
) | foreach { Write-Host $_};

Output:

01
a
01_Cleanup
02 b 02_Cleanup