PowerShell - 将两个变量合二为一 [英] PowerShell - Merge two variables into one

问题描述

我正在学习 PowerShell，所以请原谅(我确定是)一个简单的问题.

我习惯于编写 BATCH 脚本，如果我想合并 %USERDOMAIN% 和 %USERNAME% 我会:

set zFullUsername=%USERDOMAIN%\%USERNAME%回声 %zFullUsername%

如何在 PowerShell 中执行相同操作?

感谢您抽出宝贵时间.

解决方案

在 PowerShell 中，您可以通过几种不同的方式访问环境变量.我推荐的方法是使用 $env:VAR 变量来访问它们.

$user = $env:USERNAME$domain = $env:USERDOMAINecho "$domain\$user";

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注意:\ 不是 PowerShell 解析器中的转义字符，` 是.

类似于渲染 echo 命令(echo 是 Write-Output 顺便说一句的别名)，您可以创建一个用户名变量，如下所示:

$fullUserName = "$domain\$user";

或者您可以直接从环境变量中直接跳过创建 $fullUserName :

$fullUserName = "${env:USERDOMAIN}\${env:USERNAME}";

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注意:当变量中包含非字母数字字符时，${} 序列告诉 PowerShell ${} 之间的所有内容都是要扩展的变量名称的一部分.

看来 $env:VAR 中的 : 实际上是此规则的一个例外，如
Username: $env:USERNAME"; 确实渲染正确.所以上面的 ${} 序列是可选的.

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为了避免在尝试将此答案应用于其他领域时出现混淆，如果您需要在字符串本身中插入对象 property 或其他表达式的值，您将使用子表达式而是在字符串中，即 $() 序列:

$someVar = "Name: $($someObject.Name)";

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当使用 ${} 或 $() 时，不允许用空格填充外部 {} 或 ().

I'm learning PowerShell so please forgive (what I'm sure is) a simple question.

I'm used to coding BATCH scripts and if I wanted to merge %USERDOMAIN% and %USERNAME% I would:

set zFullUsername=%USERDOMAIN%\%USERNAME%
echo %zFullUsername%

How can I do the same in PowerShell?

Thank you for your time.

解决方案

In PowerShell, you can access environment variables in a few different ways. The way I recommend is to use the $env:VAR variable to access them.

$user = $env:USERNAME
$domain = $env:USERDOMAIN

echo "$domain\$user"

Note: \ is not an escape character in the PowerShell parser, ` is.

Similarly to rendering the echo command (echo is an alias of Write-Output btw) you can create a username variable like so:

$fullUserName = "$domain\$user"

Or you can skip right to creating $fullUserName straight from the environment variables:

$fullUserName = "${env:USERDOMAIN}\${env:USERNAME}"

Note: When variables have non-alphanumeric characters in them, the ${} sequence tells PowerShell everything between the ${} is part of the variable name to expand.

It seems the : in $env:VAR is actually an exception to this rule, as
"Username: $env:USERNAME" does render correctly. So the ${} sequence above is optional.

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To avoid confusion when trying to apply this answer in other areas, if you needed to insert the value of an object property or some other expression within a string itself, you would use a sub-expression within the string instead, which is the $() sequence:

$someVar = "Name: $($someObject.Name)"

When using either ${} or $(), whitespace is not allowed to pad the outer {} or ().

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