对哈希表进行排序并放入一个新的哈希表中

Question

我不明白为什么下面的循环是 return 个空键。我认为 $hashSorted 不是 Hashtable 类型；那我怎么强迫它呢？现在想想我需要一个 deep/copy 吗？我只想对我的哈希表进行排序并将其放入另一个哈希表中。

这可能是以下内容的复制品：Sort Hashtable and assign it to a new variable in Powershell 我最初的问题是为什么在执行循环时键为空。然后我意识到它可能不是哈希表。仍在尝试那里的答案。

参考：

cls
$hashFilesAndSizes = @{}
$hashSorted = @{}
$hashFilesAndSizes.Add("file1.txt",1000)
$hashFilesAndSizes.Add("file2.txt",200)
$hashFilesAndSizes.Add("file3.txt",750)
$hashFilesAndSizes.GetEnumerator() | sort value  #Displays sorted hash table 

Write-Host "Second Try - put in another hashtable"
$hashSorted = $hashFilesAndSizes.GetEnumerator() | sort value  #put into a new variable 
Write-Host "Original variable in original Order" 
$hashFilesAndSizes
Write-Host "Sorted" 
$hashSorted #show results 

Write-Host "Why loop has null keys?"

  foreach($key in $hashSorted.Keys) 
   {
      Write-Host "Key=$key" 
      #if (-not ([string]::IsNullOrEmpty($key)))
      #{
          $keyPadded = $key.PadRight(50," ")
          $fileSize = $hashSorted[$key] 
          $fileSizeFormatted = $fileSize.ToString("000,000")
          Write-Host "$keyPadded  size=$fileSizeFormatted "
      #}
   }

Write-Host "Test with enumerator"

  foreach($item in $hashSorted.GetEnumerator()) 
   {
      $key = $hashSorted.Key 
      Write-Host "Key=$key" 
      #if (-not ([string]::IsNullOrEmpty($key)))
      #{
          $keyPadded = $key.PadRight(50," ")
          $fileSize = $hashSorted.Value
          $fileSizeFormatted = $fileSize.ToString("000,000")
          Write-Host "$keyPadded  size=$fileSizeFormatted "
      #}
   }

结果：

> Name                           Value                                  
> 
> ----                           -----                                                                                                                     file2.txt                      200                                    
> file3.txt                      750                                    
> file1.txt                      1000                                   
> Second Try - put in another hashtable Original variable in original
> Order file3.txt                      750                              
> file1.txt                      1000                                   
> file2.txt                      200                                    
> Sorted file2.txt                      200                             
> file3.txt                      750                                    
> file1.txt                      1000                                   
> Why loop has null keys? Key= You cannot call a method on a null-valued
> expression. At C:\Scripts\HashTableSortTest.ps1:23 char:37
> +           $keyPadded = $key.PadRight <<<< (50," ")
>     + CategoryInfo          : InvalidOperation: (PadRight:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull   Index operation failed; the array index evaluated to null. At
> C:\Scripts\HashTableSortTest.ps1:24 char:35
> +           $fileSize = $hashSorted[ <<<< $key] 
>     + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
>     + FullyQualifiedErrorId : NullArrayIndex   You cannot call a method on a null-valued expression. At
> C:\Scripts\HashTableSortTest.ps1:25 char:50
> +           $fileSizeFormatted = $fileSize.ToString <<<< ("000,000")
>     + CategoryInfo          : InvalidOperation: (ToString:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull
>     size=  
>Test with enumerator Key= You cannot call a method on a null-valued expression. At C:\Scripts\HashTableSortTest.ps1:38 char:37
> +           $keyPadded = $key.PadRight <<<< (50," ")
>     + CategoryInfo          : InvalidOperation: (PadRight:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull   You cannot call a method on a null-valued expression. At
> C:\Scripts\HashTableSortTest.ps1:40 char:50
> +           $fileSizeFormatted = $fileSize.ToString <<<< ("000,000")
>     + CategoryInfo          : InvalidOperation: (ToString:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull
>     size=  Key= You cannot call a method on a null-valued expression. At C:\Scripts\HashTableSortTest.ps1:38 char:37
> +           $keyPadded = $key.PadRight <<<< (50," ")
>     + CategoryInfo          : InvalidOperation: (PadRight:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull   You cannot call a method on a null-valued expression. At
> C:\Scripts\HashTableSortTest.ps1:40 char:50
> +           $fileSizeFormatted = $fileSize.ToString <<<< ("000,000")
>     + CategoryInfo          : InvalidOperation: (ToString:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull
>     size=  Key= You cannot call a method on a null-valued expression. At C:\Scripts\HashTableSortTest.ps1:38 char:37
> +           $keyPadded = $key.PadRight <<<< (50," ")
>     + CategoryInfo          : InvalidOperation: (PadRight:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull   You cannot call a method on a null-valued expression. At
> C:\Scripts\HashTableSortTest.ps1:40 char:50
> +           $fileSizeFormatted = $fileSize.ToString <<<< ("000,000")
>     + CategoryInfo          : InvalidOperation: (ToString:String) [], RuntimeException
>     + FullyQualifiedErrorId : InvokeMethodOnNull
>     size=

Answer 1

尝试运行在新的清晰的 powershell 上下文中。我建议你的环境有一些变量保存在缓存中。

我看到的唯一错误是在第二个循环中。您在循环内使用 $hashSorted 而不是 $item。应该是：

  $key = $item.Key 
  ....
  $fileSize = $item.Value

编辑： 顺便说一句，使用 GetEnumerator() 排序效果很好。

编辑 2： $hashSorted.Keys 为空，因为 $hashSorted 不是哈希表，只是键值对的集合。

Answer 2

Write-Host "Test with enumerator"

  foreach($item in $hashSorted.GetEnumerator()) 
   {
      $key = $item.Key                                        # Not $hashSorted.Key !
      Write-Host "Key=$key" 
      #if (-not ([string]::IsNullOrEmpty($key)))
      #{
          $keyPadded = $key.PadRight(50," ")
          $fileSize = $item.Value                             # Not $hashSorted.Value !
          $fileSizeFormatted = $fileSize.ToString("000,000")
          Write-Host "$keyPadded  size=$fileSizeFormatted "
      #}
   }

Answer 3

这个

$hashSorted = $hashFilesAndSizes.GetEnumerator() | sort value

不会生成新的哈希表。相反，它会生成一个 DictionaryEntry 对象数组。现在，由于 $hashSorted 实际上不是哈希表，因此没有 Keys 属性并且按值索引将不起作用。要正确构建一个保留键顺序的新哈希表，您必须这样做

$hashSorted = [ordered] @{}
$hashFilesAndSizes.GetEnumerator() | sort value | foreach {$hashSorted[$_.Key] = $_.Value}

对哈希表进行排序并放入一个新的哈希表中

Sort hashtable and put into a new hashtable

powershell

enumeration

hashtable