This post isn't a stab at OOP at all.  This post is to simply show the differences in performance between Arrays and Objects.  For most applications it probably doesn't make a huge difference but if you're working on a large web application or backend job microseconds count.

I will use a snippet of code that does exactly the same thing but store the data in an object and an array.  First lets look at using an object.

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<?php
 $start = microtime(true);
 
 $a = new stdClass;
 
 for($i = 0; $i < 100000; $i++){
 $a->$i = "TEST";
 }
 
 
 $end = microtime(true);
 
 print("Processed in ".($end-$start)." seconds\n");
?>
 
 
Output: Processed in 0.081549167633057 seconds
 
 
 

Now, lets examine the difference if you use an array with string keys.

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<?php
 $start = microtime(true);
 
 $a = array();
 
 for($i = 0; $i < 100000; $i++){
 $a["key$i"] = "TEST";
 }
 
 
 $end = microtime(true);
 
 print("Processed in ".($end-$start)." seconds\n");
?>
 
 
Output: Processed in 0.089761018753052 seconds
 
 
 

As you can tell, the array with string kess performs worse than an object.   Lets examine using a numeric key.

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<?php
 $start = microtime(true);
 
 $a = array();
 
 for($i = 0; $i < 100000; $i++){
 $a[$i] = "TEST";
 }
 
 
 $end = microtime(true);
 
 print("Processed in ".($end-$start)." seconds\n");
?>
 
 
Output: Processed in 0.049083948135376 seconds
 
 
 

Look at that, nearly twice as fast as both objects and arrays with string indexes.  For the seasoned programmer this comes as no surprise, but for a more junior programmer this is something to keep in mind.  Yes, an assiciative array makes for cleaner code, but can have a pretty big impact on performance at scale.