Faster way of writing out to excel in powershell - excel

Question

I have a powershell script that reads in a csv and then appends to an excel worksheet.
It runs quite painfully slow. I have searched and it seems this is a limitation of using com to write to excel. Some suggestions I have found to speed this up are to write out entire ranges instead of cell by cell. However I need to format the cells and it doesn't seem to be possible to do this when writing out ranges. Any suggestions on how to optimize the below code would be welcome.
I do not have the option to use a DB.
$csvPath = "Z:\script_test\"
$outputFile = "Z:\script_test\exceltest.xlsx"
foreach($csvFile in Get-ChildItem $csvPath -Filter "STATS*.txt" ){
$csvFilePath = [io.path]::combine($csvPath, $csvFile)
$rawcsvData = Import-Csv -Delimiter ";" -Path $csvFilePath
$Excel = New-Object -ComObject excel.application
$Excel.visible = $false
$workbook = $Excel.workbooks.Open($outputFile)
$ExcelWorkSheet = $Excel.WorkSheets.item("2016")
$ExcelWorkSheet.activate()
$excel.cells.item(1,1) = “PEX”
$excel.cells.item(1,2) = “RUN DATE”
$excel.cells.item(1,3) = “EXECS”
$excel.cells.item(1,4) = “CPU AV.”
$excel.cells.item(1,5) = “CPU HI.”
$excel.cells.item(1,6) = “CPU TOT.”
$excel.cells.item(1,7) = “#VALUE!”
$excel.cells.item(1,8) = “ELAPS AV.”
$excel.cells.item(1,9) = “ELAPSE HI.”
$excel.cells.item(1,10) = “ELAPSE TOT”
$i = $ExcelWorkSheet.UsedRange.rows.count + 1
foreach($rawcsv in $rawcsvData)
{
$RUNDATE = $rawcsv.“RUN DATE ”.replace("--1","")
$EXECS = $rawcsv."EXECS ".replace("?","")
$CPUAV = $rawcsv.“CPU AV. ”.replace("-",":")
$CPUHI = $rawcsv.“CPU HI. ”.replace("-",":")
$CPUTOT = $rawcsv.“CPU TOT. ”.replace("-",":")
$ELAPSEAV = $rawcsv.“ELAPSE AV.”.replace("-",":")
$ELAPSEHI = $rawcsv.“ELAPSE HI.”.replace("-",":")
$ELPASETOT = $rawcsv.“ELPASE TOT”.replace("-",":")
Write-Output("working" + $i)
$excel.cells.item($i,1) = $rawcsv."PEX "
$excel.cells.item($i,2) = $RUNDATE
$excel.cells.item($i,2).NumberFormat = “yyyy/mm/dd”
$excel.cells.item($i,3) = $EXECS
$excel.cells.item($i,4) = $CPUAV
$excel.cells.item($i,4).NumberFormat = “hh:mm:ss.00”
$excel.cells.item($i,5) = $CPUHI
$excel.cells.item($i,5).NumberFormat = “hh:mm:ss.00”
$excel.cells.item($i,6) = $CPUTOT
$excel.cells.item($i,6).NumberFormat = “hh:mm:ss.00”
$excel.cells.item($i,7) = “=((HOUR(F"+$i+")*3600)+(MINUTE(F"+$i+")*60)+SECOND(F"+$i+"))*21”
$excel.cells.item($i,8) = $ELAPSEAV
$excel.cells.item($i,8).NumberFormat = “hh:mm:ss.00”
$excel.cells.item($i,9) = $ELAPSEHI
$excel.cells.item($i,9).NumberFormat = “hh:mm:ss.00”
$excel.cells.item($i,10) = $ELPASETOT
$excel.cells.item($i,10).NumberFormat = “hh:mm:ss.00”
$i++
}
$ExcelWorkSheet.UsedRange.RemoveDuplicates()
#$workbook.saveas($outputFile)
$workbook.save()
$Excel.Quit()
Remove-Variable -Name excel
[gc]::collect()
[gc]::WaitForPendingFinalizers()
Move-Item -Path $csvFilePath -Destination "Z:\script_test\used files"
}

Answer 1

The slow part is all about COM object performance. You won't be able to speed this up good enough if you will keep working with COM object, sadly.
Back in days I had some project related to Excel and I found some great module that uses external DLL, you can take a look on it: PSExcel
Best part is that you will not need to have Excel installed, like you do with COM object.

Answer 2

There is a Powershell cmdlet you can install called Export-XLSX that works very similarly to the native Export-CSV: https://gallery.technet.microsoft.com/office/Export-XLSX-PowerShell-f2f0c035
The documentation there is pretty good, but here's an example of how you would use it:
# 1. Define path of Export-XLSX.ps1 script:
$ExportXLSX = "C:\YourFilePath\Export-XLSX\Export-XLSX.ps1"
# 2. Call script same as any other function by preceding filename with a period (.$ExportXLSX) and following it with parameters:
Get-ChildItem $env:windir | Select-Object Mode,LastWriteTime,Length,Name | .$ExportXLSX -Path 'c:\temp\PSExcel.xlsx' -WorkSheetName 'Files'
UPDATE: Having compared this option with the full PSExcel module presented in the other answer, I actually prefer the PSExcel module. The performance speed-wise is pretty much the same in my testing, but the PSExcel module appears to create much smaller files.
For example, using the above list of the windows directory outputs a 53KB file using the Export-XLSX.ps1 on my machine. However, the PSExcel module outputs a 7KB file. Given its ease of use, I would go with it.