This is a collection of how to write the fastest (execution wise) performing PHP scripts. Feel free to add your share.

• Only type cast when absolutely required

  
  Type-casting slows down PHP!
  

  <?php
  
  $a = null;
  $b = null;
  $c = null;
  $max = 1e6;
  
  $start = microtime(true);
  
  for ($i = 0; $i < $max; $i++)
  {
      $a = 1234+5678+$i;
      $b = 1234*5678+$i;
      $c = 1234/2+$i;
  }
  
  var_dump(microtime(true) - $start);
  
  $start = microtime(true);
  
  for ($i = 0; $i < $max; $i++)
  {
      $a = (int)1234+(int)5678+$i;
      $b = (int)1234*(int)5678+$i;
      $c = (int)1234/(int)2+$i;
  }
  
  var_dump(microtime(true) - $start);

  
  Result
  No type casting: float(0.23545098304749)
  With type casting: float(0.35851693153381)

• Never use double quotes unless absolutely required

  
  PHP will try to evaluate variables!
  

  <?php
  $max = 1e6;
  
  ob_start();
  $start = microtime(true);
  for ($i = 0; $i < $max; $i++)
  {
  echo "microyahoodleple!!!~ ".$i;
  }
  ob_end_clean();
  var_dump(microtime(true) - $start);
  
  ob_start();
  $start = microtime(true);
  for ($i = 0; $i < $max; $i++)
  {
  echo 'microyahoodleple!!!~ '.$i;
  }
  ob_end_clean();
  var_dump(microtime(true) - $start);
  
  ob_start();
  $start = microtime(true);
  for ($i = 0; $i < $max; $i++)
  {
  echo "microyahoodleple!!!~ $i";
  }
  ob_end_clean();
  var_dump(microtime(true) - $start);

  
  Result
  Double quotes eval + concatenation: float(0.40142297744751)
  Concatenation: float(0.27414393424988)
  Double quotes eval: float(0.33820700645447)

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