Split CSV Files into smaller chunks

splitCSV.php

<?php
/*
This function was created by ChatGPT and does the following:

    1. Checks if the input file exists.
    2. Opens the input CSV file for reading.
    3. Ensures the output directory exists, creating it if necessary.
    4. Reads the header row of the CSV.
    5. Loops through each row of the input CSV file.
    6. Creates a new output file every 400 rows, including the header row.
    7. Writes each row to the current output file.
    8. Closes the input and output files appropriately.

Make sure to update the $inputFile and $outputDir variables with the correct paths for your files.
*/

// Example usage:
$inputFile = 'formidable_entries.csv';
$outputDir = 'order-form-chunks';
splitCSV($inputFile, $outputDir);

function splitCSV($inputFile, $outputDir, $rowsPerFile = 400) {
    // Check if the input file exists
    if (!file_exists($inputFile)) {
        throw new Exception("Input file does not exist.");
    }

    // Open the input CSV file for reading
    $inputHandle = fopen($inputFile, 'r');
    if (!$inputHandle) {
        throw new Exception("Failed to open the input file.");
    }

    // Ensure the output directory exists
    if (!is_dir($outputDir)) {
        mkdir($outputDir, 0777, true);
    }

    $fileCount = 0;
    $rowCount = 0;
    $headers = fgetcsv($inputHandle); // Read the header row

    $outputHandle = null;

    while (($data = fgetcsv($inputHandle)) !== false) {
        if ($rowCount % $rowsPerFile === 0) {
            // Close the current output file if open
            if ($outputHandle) {
                fclose($outputHandle);
            }

            // Create a new output file
            $fileCount++;
            $outputFileName = $outputDir . '/output_' . $fileCount . '.csv';
            $outputHandle = fopen($outputFileName, 'w');
            if (!$outputHandle) {
                throw new Exception("Failed to create output file: " . $outputFileName);
            }

            // Write the header to the new output file
            fputcsv($outputHandle, $headers);
        }

        // Write the current row to the output file
        fputcsv($outputHandle, $data);
        $rowCount++;
    }

    // Close the last output file
    if ($outputHandle) {
        fclose($outputHandle);
    }

    // Close the input file
    fclose($inputHandle);

    echo "Splitting completed. Created " . $fileCount . " files.\n";
}