powershell - 为什么 PowerShell 以不同的方式考虑 @() 语法

Question

数组初始化在 powershell 中的工作方式不同

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

输出:

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

---

请注意数组初始化中的“，”:

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

输出:

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

为什么？

Answer 1

这是因为 Comma operator 的用法不同。 (二进制 vs 一元):

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.

---

二进制:

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

输出:

01 a 01_Cleanup
02 b 02_Cleanup

---

一元:

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

输出:

01
a
01_Cleanup
02 b 02_Cleanup