數組上的組對象？

Question

如何在下列數組的前兩列（a，b）和（c，e）上使用Group-Object？

$a = @('a','b','x',10), 
@('a','b','y',20), 
@('c','e','x',50), 
@('c','e','y',30) 

Answer 1

Group-Object接受匿名計算性能，代替屬性名稱：

PS C:\> $a | Group-Object @{ Expression={$_[0]} },@{ Expression = {$_[1]} } 

它還接受一個腳本塊：

PS C:\> $a | Group-Object {$_[0]},{$_[1]} 

只要表達可以評價爲字符串：

PS C:\> Get-Help Group-Object -Parameter Property 

-Property [<Object[]>] 
    Specifies the properties for grouping. The objects are arranged into groups 
    based on the value of the specified property. 

    The value of the Property parameter can be a new calculated property. 
    To create a calculated, property, create a hash table with an Expression key 
    that specifies a string or script block value.