Erlang Parasu erlangparasu

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:

System directories

Method	Result
Environment.getDataDirectory()	/data
Environment.getDownloadCacheDirectory()	/cache
Environment.getRootDirectory()	/system

External storage directories

5 entertaining things you can find with the GitHub Search API

Let's have some command-line fun with curl, [jq][1], and the [new GitHub Search API][2].

Today we're looking for:

The hottest repositories created in the last week.
The oldest user accounts with zero followers. (So sad.)
Issue trends by language.
Clojure projects defying convention.

Multi-Threading in PHP with pthreads

A Brief Introduction to Multi-Threading in PHP

Foreword
Execution
Sharing
Synchronization
Pitfalls

	public class DeviceInfo {

	private static final String PREFERENCES = "DeviceInfo.PREFERENCES";
	private static final String KEY_DEVICEID = "DeviceId";

	/**
	* @return unique identifier string for the device
	*/
	public static synchronized String getDeviceId(Context context) {
	SharedPreferences prefs = context.getSharedPreferences(PREFERENCES, 0);

	<html>
	<body>
	<p>Here are Webber’s points:</p>
	<ul>
	<li>If a method can be static, declare it static. Speed improvement is by a factor of 4.</li>
	<li>echo is faster than print.(<em>* compare with list from phplens by John Lim</em>)</li>
	<li>Use echo’s multiple parameters instead of string concatenation.</li>
	<li>Set the maxvalue for your for-loops before and not in the loop.</li>
	<li>Unset your variables to free memory, especially large arrays.</li>
	<li>Avoid magic like __get, __set, __autoload</li>

	<?php
	function compareImages($imagePathA, $imagePathB, $accuracy){
	//load base image
	$bim = imagecreatefromjpeg($imagePathA);
	//create comparison points
	$bimX = imagesx($bim);
	$bimY = imagesy($bim);
	$pointsX = $accuracy*5;
	$pointsY = $accuracy*5;
	$sizeX = round($bimX/$pointsX);

	<?php
	/**
	* A helper file for Laravel 5, to provide autocomplete information to your IDE
	* Generated for Laravel 5.5.13 on 2017-09-28.
	*
	* @author Barry vd. Heuvel <[email protected]>
	* @see https://github.com/barryvdh/laravel-ide-helper
	*/
	namespace {
	exit("This file should not be included, only analyzed by your IDE");

	location ~ /\.git {
	deny all;
	}

	# or, all . directories/files in general (including .htaccess, etc)

	location ~ /\. {
	deny all;
	}