Question

This is my code:

$string2 = file_get_contents('maps/' . $region . '.txt');
$string2 = explode("\n", $string2);
foreach($string2 as $value2) {
   $string2 = unserialize($value2);
   if($string2['x_pos'] == ($x2 + 4) && $string2['y_pos'] == ($y2 + 8)) {
      $length2 = strlen($string2['amount']);
      $new_amount = ($string2['amount'] + 0) - ($resource_quantity + 0);
      $changed = substr_replace($value2, $new_amount, 123, $length2);
      file_put_contents('maps/' . $region . '.txt', $changed);
      break 1;
   }
}

What I want the code to do is to open the file, read each line until it finds the line it wants and then re-save the file with the edited line. The problem is, that it works, but it only saves it with the edited line, and gets rid of all of the other lines.

I want to keep with the method I’ve used (file_get_contents & file_put_contents) really, unless there is an incredibly easier way to do it. Can someone please help? I’ve been searching for some time and cannot find what I’m looking for.

Answer 1

You need to move the write operation after the loop and have it write everything you read from the file. The way you currently have it, it’s replacing all the contents with just $changed (which is just one line).

The above, in addition to improving the code a bit, leads us to:

$filename = 'maps/' . $region . '.txt';
$lines = file($filename);
foreach($lines as &$line) { // attention: $line is a reference
    $obj = unserialize($line);
    if(/* $obj satisfies your criteria*/) {
        $line = /* modify as you need */;
        break;
    }
}

file_put_contents($filename, implode("\n", $lines));