How to combine multiple CSV files in PHP-CodePudding

I have many CSV files with the same number of lines, such as the following

name   age
Tom     18
John    16
Crisp   22

countries
The United States
Britain
Japan

professional
engineer
accountant
painter

Now I want to combine them into a separate CSV that looks something like this

name   age    country            professional
Tom     18    The United States  engineer
John    16    Britain            accountant
Crisp   22    Japan              painter

Maybe I have more CSV files, and I need to synthesize them into a CSV file What should I do? Read each line of the CSV file and then write it back? Any help please

CodePudding user response：

It the files are not too big, the easiest solution is to store all the data into a global array and output it when all the data are read :

$delimiter = "\t" ;
$input_files = array('users.csv', 'countries.csv', 'professions.csv'); // files to merge

// read all the data, store them in $result
$result = array(); // final array with merged fields
foreach($input_files as $file)
{
    $reader = fopen($file, 'r');
    
    $line_index = 0 ;
    while($line = fgetcsv($reader, null, $delimiter) )
    {
        if(! array_key_exists($line_index, $result)) // if the line doesn't exist in the result yet, create it
            $result[$line_index] = array();
        
        $result[$line_index] = array_merge($result[$line_index], $line) ; // append the current field to the existing line
          $line_index;
    }    
    fclose($reader);
}

// output the result
$writer = fopen('result.csv', 'w ');
foreach($result as $row)
{
    fputcsv($writer, $row, $delimiter);
}
fclose($writer);

Output :

name    age countries   professional
Tom 18  "The United States" engineer
John    16  Britain accountant
Crisp   22  Japan   painter