哈希表中的解释点

Question

有一个哈希表：

$Main = @{
    One = 'One Value'
    Two = @{    
        Two = 'Two Value'
        Tree = @{        
            Tree = 'Tree Value'
        }    
    }
}

为什么我无法通过这种方式获取值？

# It works
$Want = 'One'
$Main.$Want

# This does not work. I get a void
$Want = 'Two.Two'
$Main.$Want

# And that of course doesn't work either
$Want = 'Two.Tree.Tree'
$Main.$Want

如何修改 $Want 字符串，使其成为可能（例如，[Something]$Want = 'Two.Tree.Tree'，我得到 Tree Value 的值 $Main.$Want）。

此刻，我做出了这样的决定。但可以肯定的是，提供了更短更快的解决方案。

$Main = @{
    One = 'One Value'
    Two = @{    
        Two = 'Two Value'
        Tree = @{        
            Tree = 'Tree Value'
        }    
    }
}

# $Want = 'One'
# $Want = 'Two.Two'
$Want = 'Two.Tree.Tree'

$Want = $Want -Split '\.'
$Want = Switch ( $Want.Length ) {

    1 { $Main.($Want[0]) }
    2 { $Main.($Want[0]).($Want[1]) }
    3 { $Main.($Want[0]).($Want[1]).($Want[2]) }
}

$Want

# Result 'Tree Value'

Answer 1

使用调用表达式：

$Want = 'Two.Two'

Invoke-Expression ('$Main.' + $Want)

哈希表中的解释点

Interpretation point in a hashtable

powershell

hashtable