PowerShell中哈希表值的字符串插值

我有一个哈希表：

$hash = @{ First = 'Al'; Last = 'Bundy' }

我知道我可以做到这一点：

Write-Host "Computer name is ${env:COMPUTERNAME}"

所以我希望这样做：

Write-Host "Hello, ${hash.First} ${hash.Last}."

…但我明白了：

Hello,  .

---

如何在字符串插值中引用哈希表成员？

如果愿意，通过添加一个小函数，您可以更通用一些。不过，请注意，您正在执行

$template

字符串中可能不受信任的代码

Write-Host "Hello, $($hash.First) $($hash.Last)."

Function Format-String ($template) 
{
    # Set all unbound variables (@args) in the local context
    while (($key, $val, $args) = $args) { Set-Variable $key $val }
    $ExecutionContext.InvokeCommand.ExpandString($template)
}

# Make sure to use single-quotes to avoid expansion before the call.
Write-Host (Format-String 'Hello, $First $Last' @hash)

# You have to escape embedded quotes, too, at least in PoSh v2
Write-Host (Format-String 'Hello, `"$First`" $Last' @hash)

无法在Powershell 4.0中工作，因此改编如下

Function Format-String ($template) 
{
  # Set all unbound variables (@args) in the local context
  while ($args)
  {
    ($key, $val, $args) = $args
    Set-Variable -Name $key.SubString(1,$key.Length-2) -Value $val
  }
  $ExecutionContext.InvokeCommand.ExpandString($template)
}

---

这需要额外的括号：Write Host（“Hello{0}{1}.-f…”这些额外的

$

符号非常难看。我希望有更好的东西。@RogerLipscombe这是Powershell，它不是一种漂亮的语言，字符串插值特别讨厌！

Function Format-String ($template) 
{
  # Set all unbound variables (@args) in the local context
  while ($args)
  {
    ($key, $val, $args) = $args
    Set-Variable -Name $key.SubString(1,$key.Length-2) -Value $val
  }
  $ExecutionContext.InvokeCommand.ExpandString($template)
}