PHP has some great functions for parsing and outputting comma separated value (CSV) files, but it falls short when it comes to returning that data as a string. Sure, you could map over the array with
implode, but what would the result of that be if you're dealing with information that contains commas within the values themselves? Luckily, you can combine PHP's built-in functions with some well-placed
stream-wrappingto fill the gaps.
First of all, the following functions are supported by PHP out-of-the-box:
- fgetcsv - Similar to fgets() except that fgetcsv() parses the line it reads for fields in CSV format and returns an array containing the fields read.
- fputcsv - Formats a line (passed as a fields array) as CSV and write it (terminated by a newline) to the specified file handle.
- str_getcsv - (PHP 5.3.0 +) Parses a string input for fields in CSV format and returns an array containing the fields read.
The snippet of code below implements a new str_putcsv, which expects an array of associative arrays, and returns a CSV formatted string.
function str_putcsv($data) {
$fh = fopen('php://temp', 'rw');
fputcsv($fh, array_keys(current($data)));
foreach ( $data as $row ) {
fputcsv($fh, $row);
}
rewind($fh);
$csv = stream_get_contents($fh);
fclose($fh);
return $csv;
}
Conclusion
The function above has evolved from a years worth of writing data export scripts for email distribution. There are other functions out there that do array to CSV conversion, but some introduce additional overhead for fixing the shortcomings of the CSV format. What I like is that the above code is clear and concise. By outsourcing the heavy-lifting to PHP's built-in fputcsv function, it doesn't have to involve things like str_replace to escape CSV values with commas or quotes.
