powershell - 在 powershell 中连接字符串内的变量

Question

我正在尝试连接字符串中的变量。

代码:

$uniqueID = "123"
$Key = '<add key="uniqueID" value="$uniqueID" />'
write-host $Key

我想要的结果:

<add key="uniqueID" value="123" />

我得到的结果:

<add key="uniqueID" value="$uniqueID" />

Answer 1

试试这个 -

$Key = "<add key=`"uniqueID`" value=`"$($uniqueID)`" />"

或

$Key = "<add key=`"uniqueID`" value=`"$uniqueID`" />"

强制 Windows PowerShell 解释双引号从字面上看，使用反引号字符。这可以防止 Windows PowerShell从将引号解释为字符串定界符。

信息 -

如果您查看 Get-Help about_Quoting_Rules，它说，

SINGLE AND DOUBLE-QUOTED STRINGS
   When you enclose a string in double quotation marks (a double-quoted
   string), variable names that are preceded by a dollar sign ($) are
   replaced with the variable's value before the string is passed to the
   command for processing.

   For example:

       $i = 5
       "The value of $i is $i."

   The output of this command is:
       The value of 5 is 5.

   Also, in a double-quoted string, expressions are evaluated, and the
   result is inserted in the string. For example:

       "The value of $(2+3) is 5."

   The output of this command is:

       The value of 5 is 5.

   When you enclose a string in single-quotation marks (a single-quoted
   string), the string is passed to the command exactly as you type it.
   No substitution is performed. For example:

       $i = 5
       'The value of $i is $i.'

   The output of this command is:

       The value $i is $i.

   Similarly, expressions in single-quoted strings are not evaluated. They
   are interpreted as literals. For example:

       'The value of $(2+3) is 5.'

   The output of this command is:

       The value of $(2+3) is 5.

您的代码未评估该值的原因是您使用单引号将变量 $key 括起来。用双引号包裹它并使用 sub-expression operator ($($UniqueID) 加上反引号就可以了，或者简单地使用 $UniqueID 也足够了。