Question

I have two System.Data.DataSet objects that I wish to compare using the Compare-Object Cmdlet. I wish to output a dataset with the columns of the original datasets but with only the differences and an additional column with the SideIndicator values calculated in the Compare-Object cmdlet.

Assuming I have these two CSV’s:

#C:\test.csv
"firstName","lastName"
"Bruce","Wayne"
"Clark","Kent"

#C:\test2.csv
"firstName","lastName"
"Peter","Parker"
"Clark","Kent"
"Jean","Grey"

I would like to use the results of:

compare-object (Get-Content C:\test.csv) (Get-Content C:\test2.csv)

to populate a dataset formatted as follows:

#desiredResult
"firstName","lastName","SideIndicator"
"Peter","Parker","=>"
"Jean","Grey","=>"
"Bruce","Wayne","<="

Thanks,
Zach

Answer 1

This should give $output the value you are looking for.

$output = Compare-Object $(Import-Csv c:\test.csv) $(Import-Csv c:\test2.csv) -Property FirstName, Lastname

When you use Get-Content of a file, it puts each line as an object of the array. This treats the firstname and lastname as a single line, which exists in both arrays. Therefore, it’s not returned with the compare-object since it is in both.

When you use Import-Csv it takes the first row as headers, and makes them properties to the array. Each line after that is added to the property based on it’s location in the .csv. This means that compare-object can compare them with different arrays, and maintain the properties to an output.