PowerShell Import-Csv列的多个CSV串联

Question

I would like to import multiple .csv files with 3 columns and 100 rows each, to a single .csv with each import going into the next 3 columns (ABC - DEF - GHI) rather than all concatenated into the first 3 columns with 1000s of rows.

I have tried Import-Csv but cannot control where the output is placed. Will I have to resort to using a COM object ( New-Object -ComObject excel.Application ) or is there a cleaner way to control which cells the import goes into?

Header lines are

PSComputerName,HotfixID,InstalledOn

But I need to have each loop to write across instead of underneath.

PSComputerName,HotfixID,InstalledOn,PSComputerName,HotfixID,InstalledOn,PSComputerName,HotfixID,InstalledOn

Answer 1

What you describe is not a typical use-case for CSVs, and Import-Csv (or Export-Csv for that matter) can't handle it at all. Both cmdlets convert the rows of a CSV to objects with properties named after the column headers or vice versa. Hence column headers MUST be unique if you want to use the *-Csv cmdlets.

The simplest approach to what you're trying to do would probably be something like this:

# read CSV data into distinct variables
$csv1 = Get-Content 'C:\path\to\1.csv'
$csv2 = Get-Content 'C:\path\to\2.csv'
$csv3 = Get-Content 'C:\path\to\3.csv'

# determine maximum number of rows
$max = $csv1.Count, $csv2.Count, $csv3.Count |
       Sort-Object
       Select-Object -Last 1

# concatenate corresponding rows from each file and write them to the output file
for ($i=0; $i -lt $csv1.Count; $i++) {
    # emulate missing rows in case the CSVs don't have the same number of rows
    $row1 = if ($csv1[$i]) {$csv1[$i]} else {',,'}
    $row2 = if ($csv2[$i]) {$csv2[$i]} else {',,'}
    $row3 = if ($csv3[$i]) {$csv3[$i]} else {',,'}

    "${row1},${row2},${row3}" | Add-Content 'C:\path\to\output.csv'
}