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Get-Node.md

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Get-Node

Get a node

Syntax

Get-Node
    -InputObject <Object>
    [-Unique]
    [-MaxDepth <Int32>]
    [<CommonParameters>]
Get-Node
    [-Path <Object>]
    [-Literal]
    [<CommonParameters>]

Description

The Get-Node cmdlet gets the node at the specified property location of the supplied object graph.

Examples

Example 1: Parse a object graph to a node instance

The following example parses a hash table to [PSNode] instance:

@{ 'My' = 1, 2, 3; 'Object' = 'Graph' } | Get-Node

PathName Name Depth Value
-------- ---- ----- -----
                  0 {My, Object}

Example 2: select a sub node in an object graph

The following example parses a hash table to [PSNode] instance and selects the second (0 indexed) item in the My map node

@{ 'My' = 1, 2, 3; 'Object' = 'Graph' } | Get-Node My[1]

PathName Name Depth Value
-------- ---- ----- -----
My[1]       1     2     2

Example 3: Change the price of the PowerShell book:

$ObjectGraph =
    @{
        BookStore = @(
            @{
                Book = @{
                    Title = 'Harry Potter'
                    Price = 29.99
                }
            },
            @{
                Book = @{
                    Title = 'Learning PowerShell'
                    Price = 39.95
                }
            }
        )
    }

($ObjectGraph | Get-Node BookStore~Title=*PowerShell*..Price).Value = 24.95
$ObjectGraph | ConvertTo-Expression
@{
    BookStore = @(
        @{
            Book = @{
                Price = 29.99
                Title = 'Harry Potter'
            }
        },
        @{
            Book = @{
                Price = 24.95
                Title = 'Learning PowerShell'
            }
        }
    )
}

for more details, see: PowerShell Object Parser and Extended dot notation

Parameters

-InputObject <Object>

The concerned object graph or node.

Type:Object
Mandatory:True
Position:Named
Default value:
Accept pipeline input:False
Accept wildcard characters:False

-Path <Object>

Specifies the path to a specific node in the object graph. The path might be either:

  • A dot-notation ([String]) literal or expression (as natively used with PowerShell)
  • A array of strings (dictionary keys or Property names) and/or integers (list indices)
  • A [PSNodePath] (such as $Node.Path) or a [XdnPath] (Extended Dot-Notation) object
Type:Object
Mandatory:False
Position:Named
Default value:
Accept pipeline input:False
Accept wildcard characters:False

-Literal

If Literal switch is set, all (map) nodes in the given path are considered literal.

Type:SwitchParameter
Mandatory:False
Position:Named
Default value:
Accept pipeline input:False
Accept wildcard characters:False

-Unique

Specifies that if a subset of the nodes has identical properties and values, only a single node of the subset should be selected.

Type:SwitchParameter
Mandatory:False
Position:Named
Default value:
Accept pipeline input:False
Accept wildcard characters:False

-MaxDepth <Int32>

Specifies the maximum depth that an object graph might be recursively iterated before it throws an error. The failsafe will prevent infinitive loops for circular references as e.g. in:

$Test = @{Guid = New-Guid}
$Test.Parent = $Test

The default MaxDepth is defined by [PSNode]::DefaultMaxDepth = 10.

Note

The MaxDepth is bound to the root node of the object graph. Meaning that a descendant node at depth of 3 can only recursively iterated (10 - 3 =) 7 times.

Type:Int32
Mandatory:False
Position:Named
Default value:
Accept pipeline input:False
Accept wildcard characters:False

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