PowerShell的特殊数组头/尾分配在哪里记录? [英] Where is PowerShell's special array head/tail assignment documented?
问题描述
我只是注意到这是有效的PowerShell代码:
I only just noticed that this is valid PowerShell code:
PS> $first, $rest = @(1, 2, 3)
此语句将第一个项目放入在 $ first
中的数组和在 $ rest
中的其余项。
This statement puts the first item in the array in $first
and the remaining items in $rest
.
PS> $first
1
PS> $rest
2
3
它甚至适用于任意数量的变量,将当前标题推入下一个变量,将尾标推入最后一个变量。您可以自己尝试。
It even works for an arbitrary number of variables, pushing the current head into the next variable and the tail into the last one. You can try that for yourself.
PS> $first, $second, $rest = @(1, 2, 3, 4)
如果没有足够的开头或结尾放入变量之一,则分配 $ null
值。即使在 $ rest
的情况下(我宁愿看到一个空数组,但无论如何)。
It seems to assign a $null
value if there aren't enough heads or tails to put into one of the variables. Even in the case of the $rest
(I'd rather have seen an empty array, but whatever).
PS> $first, $second, $rest = @(1)
PS> $first
1
PS> $second
PS> $second -eq $null
True
PS> $rest
PS> $rest -eq $null
True
PS> $rest -eq @()
False
问题和我的问题是我在任何地方都看不到此文件!我正在尝试找出何时支持。确切的实施方式。如果它适用于任何其他类型。
The problem, and my question, is that I don't see this documented anywhere! I'm trying to find out when this was supported. Exactly how it's implemented. If it works for any other types.
我检查了 about_Assignment
, about_Arrays
和 about_Splatting
,没有任何运气。
I checked about_Assignment
, about_Arrays
, and about_Splatting
, without any luck.
推荐答案
请参阅底部附近的分配多个变量
部分。 about_Assignment_Operators
。
See the section ASSIGNING MULTIPLE VARIABLES
near the bottom of about_Assignment_Operators
.
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