Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Monday, April 15, 2013

Use a hash table to create custom objects in PowerShell V3

As you continue to develop your skills in PowerShell, you will need to master the art of creating objects.  Objects are the result of your cmdlets efforts, packaged in a way that other cmdlets can use them.  A new feature to PowerShell V3 is the ability to create an object from a hash table.  This method may help with reducing the amount of typing required.

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$Obj = [PSCustomObject]@{'Prop1'="hello";

'prop2'='World';

'Prop3'=[double]5;

"Prop4" = $True}

 

Line 1 creates the variable $Obj that will store our object.  We set it equal to a hash table of type PSCustomeObject. The PSCustomeObject class is designed for this purpose.  We also add our first property called Prop1 with a value of hello.  The semicolon is used to separate properties.  We could have continued to type the remaining lines on line 1, but the use of the semicolon allows us to break up this single line into multiple lines for better readability.

Line 2 adds a second property called prop2 with a value of World.  PowerShell will automatically select the data type for both of these properties to be of type string when either single or double quotes are used to encapsulate the value.

Line 3 demonstrates how to cast a data type in the hash table.  Normally PowerShell would cast the number 5 as an integer.  In this case we are casting this property to be of type Double.

Line 4 also demonstrates type casting, but in this case as a Boolean value.

Here is our output:

PS C:\powershell> $Obj

 

Prop1 prop2 Prop3 Prop4

----- ----- ----- -----

hello World     5  True

 

And here is the member information of the object.

$Obj | GM

 

   TypeName: System.Management.Automation.PSCustomObject

 

Name        MemberType   Definition                   

----        ----------   ----------                   

Equals      Method       bool Equals(System.Object obj)

GetHashCode Method       int GetHashCode()            

GetType     Method       type GetType()               

ToString    Method       string ToString()            

Prop1       NoteProperty System.String Prop1=hello    

prop2       NoteProperty System.String prop2=World    

Prop3       NoteProperty System.Double Prop3=5        

Prop4       NoteProperty System.Boolean Prop4=True

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