appending different data to the end of each line in csv file - powershell

Question

I need to add text to the end of the header in a text/csv file and then add other text (date) at the end of each line below the header. Adding the text part is working fine but it's the exporting to a csv that's not working as expected.
The expected output is (bold text is the added text);
"Folder Name","Files","Folders","Size","Comment","ReportDate"
"\\server\share\folder","2,029,756","819,527","1,785,490,958,735"," ","1/10/2020"
Instead I'm getting;
"Length"
"61"
"74"
"88"
"118"
$Path = "C:\temp\"
$files = Get-ChildItem $Path -filter '*.csv'
ForEach ($file in $files)
{
$datetmp = $file.PSChildName.Substring(0,10)
$datetmp = $datetmp.split("_")
$date = $datetmp[1] + "/" + $datetmp[2] + "/" + $datetmp[0]
$Fullpath = $Path + $file
[System.Collections.ArrayList]$content = Get-Content $Fullpath #| %{"$_," + $date}
$rptinsert = #()
for ($i=0; $i -lt ($content.Count); $i++)
{
if ($i -eq 0)
{
$rptinsert += $content[$i] + ",""ReportDate"""
}
else
{
$rptinsert += $content[$i] + ",`"$date`""
}
}
$Report = $Path + $file.PSChildName.Substring(0, 10) + "-FileSizes2.csv"
$rptinsert | Export-Csv -path $Report -Encoding ascii -NoTypeInformation
}
I'm sure there are shorter methods to perform the some of my lines as well, just not looking for that right now. ;-)

Answer 1

To use Export-Csv the way you are expecting, you need to be inputting objects with property/value pairs. You are piping in strings. The only property a string has is Length. I would use Import-Csv to read the files, modify the returned values, and then Export-Csv to output the changed objects. Below is a blueprint that will work:
$Path = "C:\temp\"
$files = Get-ChildItem $Path -filter '*.csv'
Foreach ($file in $files) {
$datetmp = $file.Name.Substring(0,10).Split('_')
$date = $datetmp[1],$datetmp[2],$datetmp[0] -join '/'
$content = Import-Csv $file | Add-Member -MemberType NoteProperty -Name 'ReportDate' -Value $date -PassThru
$content | Export-Csv -Path ($Path + $file.Name.Substring(0, 10) + "-FileSizes2.csv") -NoType
}
The output of Import-Csv is a collection of custom objects with property names that match the header line of the CSV file. Since it appears you want the same value added to every line of a CSV file, you can just run one Add-Member command. If each line needs a different value, then you will need to loop through each line and run an Add-Member command.
Add-Member allows for adding different member types to an object. In your case, you want to add a NoteProperty type with a value.
Once the updates are complete to one CSV's contents, you can pipe those results into Export-Csv. -NoType prevents an additional header line with type information from the output.