Create Invoke-ConcatenateCSV.ps1

Author: bastienperez

Invoke-ConcatenateCSV.ps1

@@ -0,0 +1,98 @@
+<#
+.SYNOPSIS
+This script concatenates multiple CSV files into a single CSV file.
+
+.DESCRIPTION
+The Invoke-ConcatenateCSV.ps1 script concatenates multiple CSV files from a specified directory into a single CSV file, adding the source filename as the first column.
+A oneliner exists:
+Get-ChildItem -Filter *.csv | Select-Object -ExpandProperty FullName | Import-Csv | Export-Csv .\merged.csv -NoTypeInformation -Append
+But we don't have the source file name in the output file and we can handle different properties in the CSV files.
+
+.PARAMETER InputDirectory
+Specifies the directory containing the CSV files to be concatenated.
+
+.PARAMETER OutputFile
+Specifies the path and name of the output CSV file that will contain the concatenated data.
+
+.EXAMPLE
+PS C:\> .\Invoke-ConcatenateCSV.ps1 -InputDirectory "C:\CSVFiles" -OutputFile "C:\Output\Combined.csv"
+
+.NOTES
+Author: Bastien Perez
+Date: 2024/11/22
+Version: 1.2
+#>
+
+function Invoke-ConcatenateCSV {
+    [CmdletBinding()]
+    param(
+        [Parameter(Mandatory = $false)]
+        [string]$InputDirectory = '.',
+    
+        [Parameter(Mandatory = $false)]
+        [string]$OutputFile = 'Concatenated.csv',
+
+        [Parameter(Mandatory = $false)]
+        [string]$Delimiter = ';' ,
+
+        [Parameter(Mandatory = $false)]
+        [switch]$AddSourceFile
+    )
+
+    # Create empty array to store all data
+    [System.Collections.Generic.List[Object]]$allData = @()
+    # Get all CSV files in the specified directory
+    $files = Get-ChildItem -Path $InputDirectory -Filter '*.csv'
+
+    if ($files.Count -eq 0) {
+        Write-Warning "No CSV files found in directory: $InputDirectory"
+        return
+    }
+
+    foreach ($file in $files) {
+        Write-Verbose "Processing file: $($file.Name)"
+    
+        try {
+            # Import CSV content
+            Write-Verbose "Importing CSV content from: $($file.FullName)"
+            $csvContent = Import-Csv -Path $file.FullName -Delimiter $Delimiter
+        
+            # Add source filename to each row
+            foreach ($row in $csvContent) {
+                if ($AddSourceFile) {
+                    Write-Verbose "Adding source file = $($file.Name) to the row"
+                    $row.PSObject.Properties.Add('SourceFile', $file.Name)
+                }
+            
+                $newRow = @{}
+                # Add all other properties from the original row
+                foreach ($property in $row.PSObject.Properties) {
+                    Write-Verbose "Adding property: $($property.Name) = $($property.Value)"
+                    $newRow[$property.Name] = $property.Value
+                }
+            
+                # Add the modified row to our collection
+                $allData.Add([PSCustomObject]$newRow)
+            }
+        }
+        catch {
+            Write-Warning "Error processing file $($file.Name): $_"
+            continue
+        }
+    }
+
+    if ($allData.Count -gt 0) {
+        try {
+            # Export all data to the output file
+            $allData | Export-Csv -Path $OutputFile -NoTypeInformation -Encoding UTF8
+            Write-Host "Successfully concatenated $($files.Count) files to: $OutputFile"
+            Write-Host "Total rows: $($allData.Count)"
+        }
+        catch {
+            Write-Error "Error writing output file: $_"
+        }
+    }
+    else {
+        Write-Warning 'No data was collected from the CSV files'
+    }
+}