PHP標記四種風格：
// XML風格
<?php echo '<p>Order processed</p>'; ?>
// 簡短風格
<? echo '<p>Order processed</p>'; ?>
// script style
<script language='php'> echo '<p>Order processed</p>'; </script>
// ASP style, 默認此風格是禁用的
<% echo '<p>Order processed</p>'; %>
| echo | print_r | |
|---|---|---|
| 一個或多個字條 | 簡單變量的值 | 復雜類型變量的值(如: array, object) |
| 速度最快 | N/A | N/A |
| 無返回值 | 返回int | 返回boolean |
var_dump($variable)
<?php
// int
$x = 9895;
var_dump($x);
// boolean
$y = false;
var_dump($y);
// null
$nul = null;
var_dump($nul);
// array
$z = array("Volvo", "BMW", "Toyota");
var_dump($z);
constant: 常量不需要使用$符號；
<?php
define("GREETING", "constant value");
// ture means NOT case sensitive
// define("GREETING", "constant value", true);
echo GREETING;
// in class
class MyClass {
const constant = '常量值';
function showConstant() {
// do not use $this, must "self"
echo self::constant.PHP_EOL;
}
}
class
<?php
class Car {
var $color;
function Car($color = "green") {
$this->color = $color;
}
function what_color() {
return $this->color;
}
}
//
class phpClass {
var $var1;
var $var2;
var $var3 = "constant string";
// 構造函數
function __construct($par1, $par2) {
$this->var1 = $par1,
$this->var2 = $par2;
}
// 析構函數
function __destruct(void) {
// destruct some member parameter
}
function myFunc($arg1, $arg2) {
// some code here
}
// more functions
}
public, protected, private
class MyClass {
var $var = 'var'; // default is public
public $public = 'Public';
protected $protected = 'Protected';
private $private = 'Private';
// default is public
function myFunction() {
}
// public method
public function publicFunction() {
}
// protected method
protected function protectedFunction() {
}
// private method
private function privateFunction() {
}
}
interface：指定某個class必須實現哪些方法，接口中定義的方法必須都是公有的：
<?php
interface iTemplate {
public function setVariable($name, $var);
public function getHtml($template);
}
class Template implements iTemplate {
public function setVariable($name, $var) {
}
public function getHtml($template) {
}
}
abstract class: 至少一個方法聲明為抽象， 這樣的類不能實例化
<?php
abstract class AbstractClass {
// just declaration
abstract protected function prefixValue();
}
class ConcreteClass1 extends AbstractClass {
protected function prefixValue() { // some code here }
}
