New-Object PSObject –Property [HashTable]

Nice post Jeffrey! The simplifed syntax is great. But can you tell me why if I use the PowerShell V2 way my NoteProperties aren't sorted in the order I create them like they do using the V1 way?

Example:

$objectV1 = New-Object PSObject

$objectV1 | Add-Member NoteProperty FirstName MyFirstName

$objectV1 | Add-Member NoteProperty LastName MyLastName

$objectV1 | Add-Member NoteProperty Address MyAddress

$objectV1 | Add-Member NoteProperty City MyCity

$objectV1 | Add-Member NoteProperty State MyState

$objectV1 | Add-Member NoteProperty Zip MyZip

$objectV1

$objectV2 = New-Object PSObject -Property @{

   FirstName = 'MyFirstName'

   LastName = 'MyLastName'

   Address = 'MyAddress'

   City = 'MyCity'

   State = 'MyState'

   Zip = 'MyZip'

}

$objectV2

FirstName : MyFirstName

LastName  : MyLastName

Address   : MyAddress

City      : MyCity

State     : MyState

Zip       : MyZip

City      : MyCity

LastName  : MyLastName

Address   : MyAddress

State     : MyState

FirstName : MyFirstName

Zip       : MyZip

Thank you very much. I'm actually a DBA who likes to powershell and not a powershell expert who likes to be DBA. It was the way I found to solve my problem to add the objects from  various serevrs and one thing I always ask to powersehll community is to help me improve the code, optimize, and so I can understand more how I can make the necessary advantage of this fantastic shell.

Thanks for the tip!! I'm already changing my scripts!!

Thank you very much. I'm actually a DBA who likes to powershell and not a powershell expert who likes to be DBA. It was the way I found to solve my problem to add the objects for various servers and one thing I always ask to community is to help me improve the code, optimize, and so I can understand more how I can make the necessary advantage of this fantastic shell.

Thanks for the tip!! I'm already changing my scripts

Looks very nice, but doesn't help very much if you have to process text with name:value pairs from the messagage field of the security eventlog. I got about the same performance when I add the values one by one as noteproperty or when I collect them in a hash and add this in one step.

I posted the code using adding the hash as property at http://pauerschell.blogspot.com/2009/12/using-powershell-to-filter-eventlog.html

Hi Jeffrey,

I wonder why you didn't add release note which include changes since posh v1.0 on posh v2 RTM package.

When V2 RTM was released, one of the first things I did was replacing accelerators "$var = 1 | Select-Object Prop1, Prop2, ..." (well known and very effective trick) with modern native V2 approach "$var = New-Object -Property @{...}". And then, yes, I very quickly realized that in fact I often wanted properties to be in particular order, for various reasons. Thus, I had to restore old good tricks in approximately 50% of cases. This new feature is excellent, no doubts, but because of unpredictable property order it still does not cover what I expect from New-Object.

Would it be possible (for an end user or for Microsoft in a future version) to somehow apply an adapter - similar to the way array's are adapted for more flexible array use - that would honor the initial order of the hashtable's keys? Obviously it would be a breaking change to use a different implementation of IDictionary, but the unordered nature of keys in a hashtable has always made them slightly less useful in PowerShell IMHO.

I've started using PS just two weeks ago, and I am impressed. As far as scripting is involved, I was sooo much more productive, it's a delight.

But! Using PS *interactively*, as opposed to writing a batch file and executing it, is one very ugly experience. As commenting on the blog post probably is not the best communication channel, where is the proper place for me to whine and complain how bad is the PS command line interpreter?

Why is it that New-Object does not accept the most obvious (at least to me) for the TypeName Parameter namely a real Type?

e.g.

New-Object [System.Text.StringBuilder]

It's not a big deal. I'm just wondering...

@Stranger:  I did some testing and found a work around.

New-Object ([System.Text.StringBuilder])

It appears to be a problem with the PowerShell parser.

@Jason - in strangers example he was passing a string "[System.Text.StringBuilder]" but in your example the parenthases causes PowerShell to evaluate an expression which produces a Type object. Type.ToString is then used to send the string parameter New-Object expects which becomes "System.Text.StringBuilder" so the two are not equivalent.

It may seem like Stranger is sending a Type object

to New-Object but in fact the parameter parser considers that a string. Anything in parenthases is evaluated as an expression. It's by design.

Very nice! When creating tens of thousands of custom objects, though, is this method (using a hash) the best for performance?  If speed is more important than code elegance, what's the best way to create large numbers of custom objects with many (10+) new properties?  Thanks!

Hey Rinimbi, regarding the performance of PSObjects, Karl Prosser, mow, and Brandon Shell have been batting this around for a while. Check out the following URL and in the first sentence he links to other posts that benchmark various methods of creating custom objects.

http://karlprosser.com/coder/2008/06/12/generating-a-propertybag-aka-pscustomobject-in-c/

But depending on your circumstances, I've found the best way to create a huge number of objects with uniform structure is to use the Add-Type cmdlet in PowerShell 2.0 to create an on-the-fly .NET class in C# syntax.

I've started using PS just two weeks ago, and I am impressed. I am so much more productive in terms of scripting, super. Really a big thank you for explaining the Real Time problem with the PowerShell parser.