PHP Optimization Tips

This tutorial will explain many small techniques which will, hopefully, help optimize your php scripts. I considered myself a bit of a PHP pro until I started researching some of this stuff and realized that there is a whole realm of information out there about optimizing php that I didn’t know about. I hope you will be as surprised as I was about some of the things you might learn from this article.

Output of Data

So first off lets start with outputting data to the user. Here are some handy tips to remeber:

• echo is faster than print (cite)

When outputting strings:

• 
  Single quotes (’) with concatenation is faster than putting your variables inside a double quote (”) string. (cite)
  
  

  echo 'a string ' . $name;
  //is faster than
  echo "a string $name";

  
  

Or even better:

• 
  Use echo’s multiple parameters instead of string concatenation. (cite)
  
  

  echo 'this', 'is', 'a', $variable, 'string';
  //is faster than
  echo 'this' . 'is' . 'a' . $variable . 'string';

  
  

Loops and Counting

Here are some ways to make your loops and counting a bit more efficient.

• 
  Use pre-calculations and set the maximum value for your for-loops before and not in the loop. This means you are not calling the count() function on every loop. (cite)
  
  

  $max = count($array);
  for ($i = 0; $i < $max; $i++)
  //is faster than
  for ($i = 0; $i < count($array); $i++)

  
  

When checking the length of strings:

• 
  Use isset where possible in replace of strlen. (cite)
  
  

  if (!isset($foo{5})) { echo "Foo is too short"; }
  //is faster than
  if (strlen($foo) < 5) { echo "Foo is too short"; }

  
  

When incrementing:

• 
  Use pre-incrementing where possible as it is 10% faster. (cite)
  
  

  ++$i;
  //is faster than
  $i++;

  
  

And

• Incrementing an undefined local variable is 9-10 times slower than a pre-initialized one. (cite)

Variables and Functions

There are some handy things you can do with variables and functions in php to help optimize your script.

• 
  Unset or null your variables to free memory, especially large arrays. (cite)
• 
  Use require() instead of require_once() where possible. (cite)
• 
  Use absolute paths in includes and requires. It means less time is spent on resolving the OS paths. (cite)
  
  

  include('/var/www/html/your_app/test.php');
  //is faster than
  include('test.php');

  
  
• 
  require() and include() are identical in every way except require halts if the file is missing. Performance wise there is very little difference. (cite)
• 
  “else if” statements are faster than “switch/case” statements. (cite)