how to find out if csv file fields are tab delimited or comma delimited

Question

how to find out if csv file fields are tab delimited or comma delimited. I need php validation for this. Can anyone plz help. Thanks in advance.

Answer 1

I used @Jay Bhatt's solution for finding out a csv file's delimiter, but it didn't work for me, so I applied a few fixes and comments for the process to be more understandable.

See my version of @Jay Bhatt's function:

function decide_csv_delimiter($file, $checkLines = 10) {

    // use php's built in file parser class for validating the csv or txt file
    $file = new SplFileObject($file);

    // array of predefined delimiters. Add any more delimiters if you wish
    $delimiters = array(',', '\t', ';', '|', ':');

    // store all the occurences of each delimiter in an associative array
    $number_of_delimiter_occurences = array();

    $results = array();

    $i = 0; // using 'i' for counting the number of actual row parsed
    while ($file->valid() && $i <= $checkLines) {

        $line = $file->fgets();

        foreach ($delimiters as $idx => $delimiter){

            $regExp = '/['.$delimiter.']/';
            $fields = preg_split($regExp, $line);

            // construct the array with all the keys as the delimiters
            // and the values as the number of delimiter occurences
            $number_of_delimiter_occurences[$delimiter] = count($fields);

        }

       $i++;
    }

    // get key of the largest value from the array (comapring only the array values)
    // in our case, the array keys are the delimiters
    $results = array_keys($number_of_delimiter_occurences, max($number_of_delimiter_occurences));


    // in case the delimiter happens to be a 'tab' character ('\t'), return it in double quotes
    // otherwise when using as delimiter it will give an error,
    // because it is not recognised as a special character for 'tab' key,
    // it shows up like a simple string composed of '\' and 't' characters, which is not accepted when parsing csv files
    return $results[0] == '\t' ? "\t" : $results[0];
}

I personally use this function for helping automatically parse a file with PHPExcel, and it works beautifully and fast.

I recommend parsing at least 10 lines, for the results to be more accurate. I personally use it with 100 lines, and it is working fast, no delays or lags. The more lines you parse, the more accurate the result gets.

NOTE: This is just a modifed version of @Jay Bhatt's solution to the question. All credits goes to @Jay Bhatt.