如何在powershell中扩展变量? [英] How to expand variable in powershell?

问题描述

Get-WmiObject -Class win32_logicaldisk -Filter 'DeviceID="C:"'

做我想做的，

$var="C:"
Get-WmiObject -Class win32_logicaldisk -Filter 'DeviceID="{$var}"'

什么都不做.我尝试更改引号、连接字符串和其他 1000 项内容，但它们不起作用.为什么上面的例子不起作用，什么会起作用?

does nothing. I tried to change the quotes, to concatenate strings, and other 1000 things, but they didn't work. Why the above example doesn't work, and what would work?

推荐答案

当您以 '(单引号)开始字符串文字时，您正在创建一个逐字字符串 - 也就是说，每个字符串中的字符按字面解释，变量引用和表达式不会扩展！

When you start a string literal with ' (single-quotes), you're creating a verbatim string - that is, every character inside the string is interpreted literally and variable references and expressions won't expand!

如果要扩展变量，请使用 ":

Use " if you want the variable to be expanded:

$var = 'C:'
Get-WmiObject -Class win32_logicaldisk -Filter "DeviceID='$var'"

如果你的变量名有奇怪的字符，或者后面跟着一个单词字符，你可以用大括号{}在之后限定变量名$:

If your variable name has weird characters, or is followed by a word character, you can qualify the variable name with curly brackets {} immediately after the $:

$var = 'C:'
Get-WmiObject -Class win32_logicaldisk -Filter "DeviceID='${var}'"

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