在Powershell中更新变量中的变量：

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英文:

Updating variables within variables in Powershell

问题

我不太了解PowerShell，但我尝试学习。
你能帮助我理解和解决我想做的事情吗：

  1. $string1 = ""
  3. $complicatedString1 = "这是一个复杂的 $string1"
  4. $complicatedString2 = "$complicatedString1 也是"
  6. $string1 = "测试"
  8. $complicatedString1 -> 现在应该是: 这是一个复杂的 测试
  9. $complicatedString2 -> 现在应该是: 这是一个复杂的 测试 也是
  11. $string1 = "问题"
  13. $complicatedString1 -> 现在应该是: 这是一个复杂的 问题
  14. $complicatedString2 -> 现在应该是: 这是一个复杂的 问题 也是
  16. 等等。

这个想法听起来很简单：我想定义作为模板的字符串，但带有可变内容。在这种情况下，我想操作$string1并更新$complicatedString1和$complicatedString2，以便$string1的任何更改都会反映在这些字符串中。

$string1会经常更改，目前我还没有方法将更改后的值传递到这些字符串中。基本上它们只是等待被更改的占位符。

英文:

I don't know much about Powershell but I try to learn.
Can you help me to understand and solve what I want to do:

  1. $string1=""
  3. $complicatedString1 = "This is a complicated $string1"
  4. $complicatedString2 = "$complicatedString1 too"
  6. $string1 = "Test"
  8. $complicatedString1 -> Should state now: This is a complicated Test
  9. $complicatedString2 -> Should state now: This is a complicated Test too.
  11. $string1 = "question"
  13. $complicatedString1 -> Should state now: This is a complicated question
  14. $complicatedString2 -> Should state now: This is a complicated question too.
  16. and so on.

The idea sounds simple: I want to define strings that serve as templates, but with variable content.
In this case I want to manipulate $string1 and update $complicatedstring 1 and 2 so that any change of $string1 gets reflected in those strings.

$string1 would change frequently and at the moment I have no approach how get the changed values into those strings. Basically the're just placeholders to wait for being changed.

答案1

得分: 1

我不太确定，但我认为你的问题是关于如何使用可以更改的模板字符串。

我认为最优雅的方法是利用PowerShell的-f格式运算符，如下所示：

  1. # 模板字符串
  2. $complicatedString1 = "这是一个复杂的 {0}"
  3. $complicatedString2 = "{0} 也是"
  5. # 使用模板字符串返回新字符串
  6. $string1 = $complicatedString1 -f "测试"                # --> "这是一个复杂的测试"
  7. $string2 = $complicatedString2 -f $string1              # --> "这是一个复杂的测试 也是"
  9. $string1 = $complicatedString1 -f "问题"            # --> "这是一个复杂的问题"
  10. $string2 = $complicatedString2 -f $string1              # --> "这是一个复杂的问题 也是"

你也可以使用字符串对象自己的Format方法，如果你喜欢的话，它会给你完全相同的结果。

英文:

I'm not quite sure, but I think your question is about using template strings you can alter using new strings-to-insert.

The most elegant way to do that I think is by making use of the PowerShell -f format operator like this:

  1. # the template strings
  2. $complicatedString1 = "This is a complicated {0}"
  3. $complicatedString2 = "{0} too"
  5. # use the template strings to return new strings
  6. $string1 = $complicatedString1 -f "Test"                # --> "This is a complicated Test"
  7. $string2 = $complicatedString2 -f $string1              # --> "This is a complicated Test too"
  9. $string1 = $complicatedString1 -f "question"            # --> "This is a complicated question"
  10. $string2 = $complicatedString2 -f $string1              # --> "This is a complicated question too"

You can also use the Format method of the string object itself if you like:

  1. $string1 = [string]::Format($complicatedString1, "Test")
  2. $string2 = [string]::Format($complicatedString2, $string1)

which will give you the exact same results

答案2

得分: 0

为此，您需要将 complicatedString1 和 complicatedString2 放在单引号中（否则它们将直接展开），然后可以使用 $ExecutionContext.InvokeCommand.ExpandString 方法：

  1. $complicatedString1 = '这是一个复杂的 $string1'
  2. $complicatedString2 = '$complicatedString1 也是'
  4. $string1 = '测试'
  6. $ExecutionContext.InvokeCommand.ExpandString($complicatedString1)
  7. 这是一个复杂的 测试
  8. $ExecutionContext.InvokeCommand.ExpandString($ExecutionContext.InvokeCommand.ExpandString($complicatedString2))
  9. 这是一个复杂的 测试 也是
  11. $string1 = '问题'
  13. $ExecutionContext.InvokeCommand.ExpandString($complicatedString1)
  14. 这是一个复杂的 问题
  15. $ExecutionContext.InvokeCommand.ExpandString($ExecutionContext.InvokeCommand.ExpandString($complicatedString2))
  16. 这是一个复杂的 问题 也是
  18. *请注意，您需要两次在 `$complicatedString2` 上使用 `ExpandString` 方法，才能获得 `$string1` 展开的最终结果。*
  20. 为了更好地了解情况，您可以考虑创建一个带有 `-Depth` 参数的递归函数：
  22. ```powershell
  23. Function Expand([String]$String, [Int]$Depth = 1) {
  24. 	$Expand = $ExecutionContext.InvokeCommand.ExpandString($String)
  25. 	If ($Depth-- -ge 0) {Expand $Expand $Depth} Else {$Expand}
  26. }
  28. $string1 = '测试'
  30. Expand $complicatedString1
  31. 这是一个复杂的 测试
  32. Expand $complicatedString2 -Depth 2
  33. 这是一个复杂的 测试 也是
英文:

For this you need to put you complicatedString1 and complicatedString2 in single quotes (otherwise they will be directly expanded), than you might use the $ExecutionContext.InvokeCommand.ExpandString method:

  1. $complicatedString1 = 'This is a complicated $string1'
  2. $complicatedString2 = '$complicatedString1 too'
  4. $string1 = 'Test'
  6. $ExecutionContext.InvokeCommand.ExpandString($complicatedString1)
  7. This is a complicated Test
  8. $ExecutionContext.InvokeCommand.ExpandString($ExecutionContext.InvokeCommand.ExpandString($complicatedString2))
  9. This is a complicated Test too
  11. $string1 = "question"
  13. $ExecutionContext.InvokeCommand.ExpandString($complicatedString1)
  14. This is a complicated question
  15. $ExecutionContext.InvokeCommand.ExpandString($ExecutionContext.InvokeCommand.ExpandString($complicatedString2))
  16. This is a complicated question too

Note that you will need to use the ExpandString method twice on the $complicatedString2 to get to the bottom of the $string1 expansion.

To get a better overview, you might consider to create a recursive function with a -Depth parameter:

  1. Function Expand([String]$String, [Int]$Depth = 1) {
  2. 	$Expand = $ExecutionContext.InvokeCommand.ExpandString($String)
  3. 	If ($Depth-- -ge 0) {Expand $Expand $Depth} Else {$Expand}
  4. }
  6. $string1 = 'Test'
  8. Expand $complicatedString1
  9. This is a complicated Test
  10. Expand $complicatedString2 -Depth 2
  11. This is a complicated Test too

答案3

得分: 0

你也可以通过循环来实现它。

  1. do {
  2.     $string1 = Read-Host "请输入一个单词"
  3.     $complicatedString1 = "这是一个复杂的 $string1"; $complicatedString1
  4.     $complicatedString2 = "$complicatedString1 too`n"; $complicatedString2
  5. } while ($string1 -ne "退出程序")

输出

  1. 请输入一个单词：测试
  2. 这是一个复杂的 测试
  3. 这是一个复杂的 测试 too
  5. 请输入一个单词：问题
  6. 这是一个复杂的 问题
  7. 这是一个复杂的 问题 too
  9. 请输入一个单词：退出程序
  10. 这是一个复杂的 退出程序
  11. 这是一个复杂的 退出程序 too
  12. #程序退出#
英文:

You can also do it via a loop

  1. do {
  2.     $string1 = Read-Host "Please enter a word"
  3.     $complicatedString1 = "This is a complicated $string1"; $complicatedString1
  4.     $complicatedString2 = "$complicatedString1 too`n"; $complicatedString2
  5. } while ($string1 -ne "exit program")

Output

  1. Please enter a word: Test
  2. This is a complicated Test
  3. This is a complicated Test too
  5. Please enter a word: Question
  6. This is a complicated Question
  7. This is a complicated Question too
  9. Please enter a word: Exit Program
  10. This is a complicated Exit Program
  11. This is a complicated Exit Program too
  12. #Program Exits#

huangapple
  • 本文由 发表于 2020年1月3日 16:39:27
  • 转载请务必保留本文链接：https://go.coder-hub.com/59575416.html
  • powershell
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