您可以将Select-Object -ExpandProperty与常用的-PipelineVariable参数结合起来并进行克隆（PSv3 +语法）：

对于[pscustomobject]或[hashtable]实例的输入集合：

# Sample input array of custom objects to expand by .RecordDate
$array =
  [pscustomobject] @{ RecordDate = 1,2; OtherProp1 = 'one'; OtherProp2 = 'two' },[pscustomobject] @{ RecordDate = 3,4; OtherProp1 = 'three'; OtherProp2 = 'four' }

# Write the array elements to the pipeline,and store each in variable
# $objectOrHashtable for use in a later pipeline segment.
Write-Output $array -PipelineVariable objectOrHashtable |
  # Expand the input object's .RecordData property,i.e. send its
  # elements one by one to the next pipeline segment.
  Select-Object -ExpandProperty RecordDate | 
    ForEach-Object {
      # Clone the original input object.
      $clone = if ($objectOrHashtable -is [Management.Automation.PSCustomObject]) {
        $objectOrHashtable.psobject.Copy()
      } else { # assume [hashtable] or a type that implements [System.ICloneable]
        $objectOrHashtable.Clone()
      }
      # Assign the record date at hand to the clone...
      $clone.RecordDate = $_
      # ... and output it.
      $clone
    }

上面的结果如下：请注意，根据枚举输入对象的.RecordDate数组的元素，同时保留了所有其他属性，输出了4个对象：

RecordDate OtherProp1 OtherProp2
---------- ---------- ----------
         1 one        two
         2 one        two
         3 three      four
         4 three      four

注意：

• 以上内容适用于两种类型的输入对象：

  • 自定义对象（[pscustomobject]实例，例如由Import-Csv创建的实例）

    • 注意：出于技术原因，您不能使用-is [pscustomobject]，而必须使用完整类型名称System.Management.Automation.PSCustomObject（可以省略System.前缀）；由于历史原因，[pscustomobject]与[psobject]（System.Management.Automation.PSObject）相同，并且-is [psobject]对于未自定义的对象也适用对象。

  • 哈希表（System.Collections.Hashtable个实例，但不是[ordered]哈希表）；更一般而言，任何实现System.ICloneable的类型。

• 对自定义对象和哈希表执行的克隆是 shallow （按成员），但是具有标量字符串和数字值就足够了。

  • 通常，ICloneable接口没有规定克隆行为的细节，因此通常不鼓励使用它。

对于[System.Data.DataRow]实例的输入集合：

克隆System.Data.DataRow实例的集合-数据表的行System.Data.DataTable-需要 custom 克隆逻辑，但是方法和结构的输出基本上是相同的：

# Create a sample DataTable...
$dt = [System.Data.DataTable]::new('sample')
# ... define the columns ...
$dt.Columns.AddRange([System.Data.DataColumn[]] (
  @{ ColumnName = 'RecordDate'; DataType = [object[]] },@{ ColumnName = 'OtherProp1'; DataType = [string] },@{ ColumnName = 'OtherProp2'; DataType = [string] }
))
# ...and add sample rows.
@{ RecordDate = 1,@{ RecordDate = 3,4; OtherProp1 = 'three'; OtherProp2 = 'four' } | % {
  $dt.Rows.Add(($dr = $dt.NewRow()))
  foreach ($entry in $_.GetEnumerator()) {
    $dr[$entry.Key] = $entry.Value 
  }  
}

# Create an auxiliary,empty clone of the input data table
# to facilitate cloning of individual rows.
$dtAux = $dt.Clone()

# Write the data rows to the pipeline,and store each in variable
# $obj for use in a later pipeline segment.
Write-Output $dt.Rows -PipelineVariable row |
  # Expand the input object's .RecordData property,i.e. send its
  # elements one by one to the next pipeline segment.
  Select-Object -ExpandProperty RecordDate |
    ForEach-Object {
      # Clone the data row at hand.
      $dtAux.Clear(); $dtAux.ImportRow($row)
      $clone = $dtAux.Rows[0]
      # Assign the record date at hand to the clone...
      $clone.RecordDate = @($_)
      # ... and output it.
      $clone
    }