CODEWITHSUNDEEP
powershell
Sperry
Sperry

Reputation: 447

Modify/transform data in Select-Object

Say I've got a list of items. I'd like to export to csv, but I want to do some calculations / modifications before I do so.

Basically, the setup looks like this:

PS C:\Files> gci
Directory: C:\Files

Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---        10/23/2014   6:03 PM      11084 Blob.txt
-a---        10/13/2014   1:32 PM      31591 dates.txt
-a---         2/11/2014   1:46 PM      11990 out.txt

PS C:\Files> $data = gci

And I can select the items I want to put into CSV easily enough. The actual Export-CSV part is omitted for brevity 

PS C:\Files> $data | Select-Object FullName,name

But what I REALLY want to do is calculate a few columns and also include those in the CSV. Just as an example, say I want to count the '\' characters to get an idea of the folder depth. I think you can tell what I am trying here, even though it errors out. 

PS C:\Files> $data | Select-Object FullName,name,FullName.Split('\').Count
Select-Object : A positional parameter cannot be found that accepts argument '1'.

Is there a way to get this to work?

Upvotes: 13

Views: 15689

Answers (3)

TheMadTechnician
TheMadTechnician

Reputation: 36297

What you need is a calculated property (thank you Ansgar Wiechers for correcting my terminology and providing a link) to do that for you. You can accomplish this in a Select command by creating a kind of impromptu hashtable like so:

PS C:\Files> $data | Select-Object FullName,name,@{name='FolderDepth';expression= {$_.FullName.Split('\').Count}}

That could be shortened to @{n='Name';e={scriptblock}} where n stands for name, and is interchangeable with l (short for label). e is short for expression.

Upvotes: 21

Matt
Matt

Reputation: 46710

Yes. What you are looking for is more complex Select-Object statement using calculated property. Sample syntax:

@{Label = "Calculation";Expression ={$_.FullName.Split('\').Count}}

Then you insert this into a select statement, usually with other variables. 

$data | Select-Object FullName,name,@{Label = "TheCount";Expression ={$_.FullName.Split('\').Count}}

Upvotes: 3

Paul
Paul

Reputation: 5861

My Proposal (also a bit more readable then doing it in select):

$data | % {Add-Member -name FolderDepth -Value $_.FullName.split("\").Count -MemberType NoteProperty -InputObject $_} | select FullName,Name,FolderDepth

This adds a Property to $data which you can use further in the Pipeline with $_.FolderDepth just like any other property.

What makes this different is this property will also be available after the pipeline if you want to do stuff with it afterwards

Upvotes: 0

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