合并多个CSV文件

I am Trying to Merge Multiple CSV Files but unable to do that. Please have a look my code I dont know whats wrong with my code. csvfiles is a directory which contains multiple same format Files.

Download Sample CSV Files

My Code

$csvdir = "./csvfiles/";
$result = fopen('./csvfiles/merge.csv', 'w');
$test="";
if (is_dir($csvdir)) {
    if ($handle = opendir($csvdir)){
        while (($file = readdir($handle)) !== false) {
            if (substr($file, -4) === ".csv") {
                $csvcontent = file_get_contents($file);
                fwrite($result, $csvcontent);
            }
        }
        closedir($handle);
    }
}
fclose($result);

Some observations:

• At some point opendir($csvdir) will also include your merge.csv file. You want to avoid that. Keep it seperate.

• Keep file operations at minimum. For every .csv file in your loop you write to your merge.csv. Instead, collect the data to write in your loop and write only once.

• You're getting the wrong file contents in file_get_contents($file);. $file will only contain the filename, not the complete path.

• $test is never used.

Here's working code:

<?php

$csvdir = "./csvfiles/";
$csvcontent = '';
if (is_dir($csvdir)) {
    if ($handle = opendir($csvdir)) {
        while (($file = readdir($handle)) !== false) {
            if (substr($file, -4) === ".csv") {
                $csvcontent .= file_get_contents($csvdir . $file);
            }
        }
        closedir($handle);
    }
}

$result = fopen('./merge.csv', 'w');
fwrite($result, $csvcontent);
fclose($result);