Adam Elsodaney adamelso

Why objects (usually) use less memory than arrays in PHP

This is just a small post in response to [this tweet][tweet] by Julien Pauli (who by the way is the release manager for PHP 5.5). In the tweet he claims that objects use more memory than arrays in PHP. Even though it can be like that, it's not true in most cases. (Note: This only applies to PHP 5.4 or newer.)

The reason why it's easy to assume that objects are larger than arrays is because objects can be seen as an array of properties and a bit of additional information (like the class it belongs to). And as array + additional info > array it obviously follows that objects are larger. The thing is that in most cases PHP can optimize the array part of it away. So how does that work?

The key here is that objects usually have a predefined set of keys, whereas arrays don't:

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	// this simply blocks the GET
	// needs to be in crx background with webRequest and webRequestBlocking in permissions

	var host = 'd16fk4ms6rqz1v.cloudfront.net';

	var blocking = [
	`verical.js`
	];

	# Change YOUR_TOKEN to your prerender token
	# Change http://example.com (server_name) to your website url

	frontend my-frontend
	mode http
	bind :80

	# prerender.io
	acl user-agent-bot hdr_sub(User-Agent) -i baiduspider twitterbot facebookexternalhit rogerbot linkedinbot embedly showyoubot outbrain pinterest slackbot vkShare W3C_Validator
	acl url-asset path_end js css xml less png jpg jpeg gif pdf doc txt ico rss zip mp3 rar exe wmv doc avi ppt mpg mpeg tif wav mov psd ai xls mp4 m4a swf dat dmg iso flv m4v torrent ttf woff

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	with_items:
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	action: apt_repository repo='ppa:webupd8team/java'

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	" Install: $HOME/.vim/plugin/vagrant.vim
	" Author: Brandon Philips <[email protected]>

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	au BufRead,BufNewFile Vagrantfile set filetype=ruby
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	# sudo apt-get install scala

	#2nd way
	sudo apt-get remove scala-library scala
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	namespace Acme\Bundle\UserBundle\Form;

	use Symfony\Component\Form\AbstractType;
	use Symfony\Component\Form\FormEvents;
	use Symfony\Component\Form\FormBuilderInterface;
	use Symfony\Component\Form\FormEvent;

	class UserType extends AbstractType

	$ ack --php 'class [\w]+'\|grep -v '//'\|grep -v ''\|grep -v '>'\|sed 's/.class //'\|sed 's/ .*//'
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	WP_Widget_Factory
	WP_Embed
	Moxiecode_JSONReader
	Moxiecode_JSON
	Moxiecode_Logger
	GoogleSpell
	PSpell
	SpellChecker

	add_theme_support('menus');

	/*
	http://codex.wordpress.org/Function_Reference/register_nav_menus#Examples
	*/
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	'top-bar-r' => 'Right Top Bar'
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