niden

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:

niden

<?php
/**
 * \ND\Model
 * Model.php
 *
 * Model
 *
 * @author      Nikos Dimopoulos <nikos@niden.net>
 * @since       2012-12-12
 * @category    Library

niden

<?php
/**
 * \NDN\Api\Bootstrap
 * Bootstrap.php
 *
 * Bootstraps the API application
 *
 * @author      Nikos Dimopoulos <nikos@niden.net>
 * @since       2012-12-03
 * @category    Library

niden

<?php
/**
 * CIDR.php
 *
 * Utility Functions for IPv4 ip addresses. 
 * Supports PHP 5.3+ (32 & 64 bit)
 * @author Jonavon Wilcox <jowilcox@vt.edu>
 * @revision Carlos Guimarães <cvsguimaraes@gmail.com>
 * @version Wed Mar  12 13:00:00 EDT 2014
  */

niden

## Configure eth0
#
# vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE="eth0"
NM_CONTROLLED="yes"
ONBOOT=yes
HWADDR=A4:BA:DB:37:F1:04
TYPE=Ethernet
BOOTPROTO=static

niden

        // Send it out to the client
        $response = new PhResponse();
        $response
            ->setContentType('application/pdf')
            ->setHeader('Content-Description', 'File Transfer')
            ->setHeader('Content-Disposition', sprintf('attachment; filename=%s.pdf', $filename))
            ->setHeader('Content-Transfer-Encoding', 'binary')
            ->setHeader('Connection', 'Keep-Alive')
            ->setHeader('Expires', 0)
            ->setHeader('Cache-Control', 'must-revalidate, post-check=0, pre-check=0')

niden

#!/bin/bash
# This way you can customize which branches should be skipped when
# prepending commit message.
if [ -z "$BRANCHES_TO_SKIP" ]; then
  BRANCHES_TO_SKIP=(master develop test)
fi
BRANCH_NAME=$(git symbolic-ref --short HEAD)
BRANCH_NAME="${BRANCH_NAME##*/}"
BRANCH_EXCLUDED=$(printf "%s\n" "${BRANCHES_TO_SKIP[@]}" | grep -c "^$BRANCH_NAME$")
BRANCH_IN_COMMIT=$(grep -c "\[$BRANCH_NAME\]" $1)

niden

AddDefaultCharset UTF-8

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^(.+)\.(\d+)\.(bmp|css|cur|gif|ico|jpe?g|js|png|svgz?|webp|webmanifest)$ $1.$3 [L]

    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^((?s).*)$ index.php?_url=/$1 [QSA,L]

niden

Order of evaluation in PHP

Yesterday I found some people on my [favorite reddit][lolphp] wonder about the output of the following code:

<?php

$a = 1;
$c = $a + $a++;

niden

Verifying my Blockstack ID is secured with the address 1CsemQRtkYRhqEAaN2HJskR6iicQ9rEJSn https://explorer.blockstack.org/address/1CsemQRtkYRhqEAaN2HJskR6iicQ9rEJSn