Pass object association by reference via & to save resources
Pass object association by reference via & to save resources
Not really a big deal, but could save resources on larger arrays. Is also a clean code practice to avoid awkward traversing array and assigning to ‘itself’ from what is essentially a sub routine.
Does it really matter? Likely not. Using the below script on my 2.66 Core i7 with 8gigs of ram passing by reference is roughly 3-4 times faster. At 100000 array key value pairs the difference is still in microseconds (less than half a millisecond).
More information here: http://php.net/manual/en/language.references.pass.php
| 123456789101112131415161718192021222324252627282930 | <?php // want to loop over an array$an_array = array(); // lets populate it with random valuesfor ($i=0; $i < 100000; $i++) { $an_array[$i] = md5(uniqid(uniqid("",true),true));} // startvar_dump(microtime(true)); // now lets maniuplate the 'old' wayforeach ($an_array as $key => $value) {// this modifies the value at the index using the array and key$an_array[$key] = "ref original array and key";} var_dump(microtime(true)); // lets do it the 'new' way, notice we are passing &foreach ($an_array as $key => &$value) {// $value is a reference to the $an_array[$key]$value = "changes source array";}// finishvar_dump(microtime(true)); ?> |
| — | — |
Sample Executions
| Object | Pass reference |
|---|---|
| 445 | 123 |
| 455 | 122 |
| 443 | 122 |
| 452 | 119 |
| 446 | 129 |
*Note* times in microseconds
Author’s Note
Initial md Generated using https://github.com/jsr6720/wordpress-html-scraper-to-md
Original Wordpress categories: [‘PHP’]
Original Wordpress tags: “PHP”, “association”, “clean code”, “php”, “resource management”, “traverse array”
Original Wordpress comments: None
Significant revisions
tags: 2011, wordpress, txcowboycoder, php, clean-code, performance
- May 6th, 2024 Converted to jekyll markdown format and copied to personal site
- Jun 15th, 2011 Originally published on txcowboycoder wordpress site