How to read multiple files in parallel?

I have a number of text files that I need to open, then allocate certain fields to set strings inside PHP to eventually write into MySQL.

Each txt file does have the same unique value for app_id, eg

So text file 1 has

app_id name description

text file 2 has

app_id category

text file 3 has

app_id price

I want to get name, description, category and price for each record, and write that into mysql.

I can read the first one using code :

$fp = fopen('textfile1','r');
if (!$fp) {echo 'ERROR: Unable to open file.</table></body></html>'; exit;}
while (!feof($fp)) {
$line = stream_get_line($fp,4096,$eoldelimiter); 
if ($line[0] === '#') continue;  //Skip lines that start with # 
 $field[$loop] = explode ($delimiter, $line);
list($app_id, $name, $description) = explode($delimiter, $line);
 $fp++;
}

fclose($fp);
?> 

My question is how to read the 2nd and 3rd files? Can I somehow do it in parallel, or do I need to finish reading text file 1, write each line into mysql then open tex开发者_JS百科t file 2 and write category into mysql using replace on the app_id key, then do the same with text file 3 opening and ?

I would recommend the following approach:

• create a simple class containing the following fields: name, description, category, and price
• create an empty array that will be indexed with the app_id, each corresponding to an instance of the aforementioned class

• read each file and affect the result to the correct element in the array

  if (!isset($array[$app_id])) $array[$app_id] = new MyClass();

  array[$app_id]->name = $name;

  array[$app_id]->description = $description;

• once you're done reading all files, you can iterate through the array and write each element to the SQL table.

Simply open all three files in sequence and then have three stream_get_line's in your while loop, one for each file:

$fp1 = fopen('textfile1','r');

$fp2 = fopen('textfile2','r');

$fp3 = fopen('textfile3','r');

while (!feof($fp1)) {

$line1 = stream_get_line($fp1...)

$line2 = stream_get_line($fp2...)

$line3 = stream_get_line($fp3...)

...

You'll have to take care that each file has exactly the same number of lines, though. Best is probably to check for feof on each stream before reading a line from it, and aborting with an error message if one of the streams runs out of lines before the others.

Try this:

     file1.txt contents:
            id 13 category test description test
    file2.txt:
       id 13 name test description test
       id 15 name test description test
       id 17 name test description test


    $files = array('file1.txt','file2.txt');

            foreach($files as $file) {
                flush();
                preg_match_all("/id\s(?<id>\d+)\s(?:name|category|price)?\s(?<name>[\w]+)\sdescription\s(?<description>[^\n]+)/i",@file_get_contents($file),$match);
                    print_r($match);
            }

returns:
Array
(
    [0] => Array
        (
            [0] => id 13 category test description test
        )

    [id] => Array
        (
            [0] => 13
        )

    [1] => Array
        (
            [0] => 13
        )

    [name] => Array
        (
            [0] => test
        )

    [2] => Array
        (
            [0] => test
        )

    [description] => Array
        (
            [0] => test
        )

    [3] => Array
        (
            [0] => test
        )

)
Array
(
    [0] => Array
        (
            [0] => id 13 name test description test
            [1] => id 15 name test description test
            [2] => id 17 name test description test
        )

    [id] => Array
        (
            [0] => 13
            [1] => 15
            [2] => 17
        )

    [1] => Array
        (
            [0] => 13
            [1] => 15
            [2] => 17
        )

    [name] => Array
        (
            [0] => test
            [1] => test
            [2] => test
        )

    [2] => Array
        (
            [0] => test
            [1] => test
            [2] => test
        )

    [description] => Array
        (
            [0] => test
            [1] => test
            [2] => test
        )

    [3] => Array
        (
            [0] => test
            [1] => test
            [2] => test
        )

)