Question:
Given the following sample script (saved as sample.txt on my hard drive):
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DECLARE @xVar XML SET @xVar = ' ' SELECT nref.value('first-name[1]', 'nvarchar(50)') FirstName, nref.value('last-name[1]', 'nvarchar(50)') LastName FROM @xVar.nodes('//author') AS R(nref) WHERE nref.exist('.[first-name != "David"]') = 1 |
I want to extract the XML and determine if any child nodes have been added to node book. For this use case, assume that author is the new node.
I have written a script that works, but it seems grossly inefficient:
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Set-StrictMode -Version Latest cls #The list of fields that I want to find [array]$expected_fields = "title", "price" #extract the xml from sample.txt and put it in an xml variable [string]$file_script = Get-Content "C:\PowerShellScripts\sample.txt" [int]$start_pos = $file_script.IndexOf("'") + 1 [int]$end_pos = $file_script.SubString($start_pos + 1).IndexOf("'") + 1 [xml]$xml_result = $file_script.SubString($start_pos,$end_pos) #NOTE: THIS IS THE PART THAT FEELS WRONG #Convert the xml snipput into CSV file and then get the headers (which is the only thing I want) $export_file_name = "C:\PowerShellScripts\test.csv" Select-Xml 'child::bookstore/book' $xml_result | Select-Object -expand Node | Export-Csv $export_file_name -NoTypeInformation -Delimiter:"`t" -Encoding:UTF8 [string]$field_names = Get-Content $export_file_name | Select-Object -first 1 Remove-Item "C:\Users\Jennifer\Google Drive\PowerShellScripts\test.csv" [array]$found_fields = $field_names.Replace("""","").Split("`t") #report new fields foreach ($specific_field in $found_fields) { if ($expected_fields -notcontains $specific_field) { Write-Host "New field found:" $specific_field } } |
Is there a better way to populate *$found_fields* rather than creating a CSV file, storing the first row in a variable and then deleting the CSV file?
Answer:
Try changing your -Expand from Node to Name (and Where-Object to exclude title and price)
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$xml_result.SelectNodes("bookstore/book/*") | Select-Object -Expand Name | Where-Object { ($_ -ne "title") -and ($_ -ne "price") } |
This will give you any unexpected child nodes of book.