PHP中对象和类之间的区别? [英] Difference between object and class in PHP?
问题描述
PHP中的Object和Class有什么区别?
What is the difference between Object and Class in PHP? I ask because, I don't really see the point to both of them.
你能用好例子告诉我们的区别吗?
Can you tell me the difference with a good example?
推荐答案
我假设您有在基本PHP OOP上阅读手册。
类用于 define 对象的属性,方法和行为。对象是类中创建的事物。将类视为一个蓝图,将一个对象作为实际的构建,按照蓝图(类)构建。
A class is what you use to define the properties, methods and behavior of objects. Objects are the things you create out of a class. Think of a class as a blueprint, and an object as the actual building you build by following the blueprint (class). (Yes, I know the blueprint/building analogy has been done to death.)
// Class
class MyClass {
public $var;
// Constructor
public function __construct($var) {
echo 'Created an object of MyClass';
$this->var = $var;
}
public function show_var() {
echo $this->var;
}
}
// Make an object
$objA = new MyClass('A');
// Call an object method to show the object's property
$objA->show_var();
// Make another object and do the same
$objB = new MyClass('B');
$objB->show_var();
这里的对象是不同的(A和B),但它们都是 MyClass
类。回到蓝图/建筑类比,认为它是使用相同的蓝图建造两个不同的建筑物。
The objects here are distinct (A and B), but they are both objects of the MyClass
class. Going back to the blueprint/building analogy, think of it as using the same blueprint to build two different buildings.
这是另一个片段,实际上谈论建筑物,如果你需要一个更多字面示例:
Here's another snippet that actually talks about buildings if you need a more literal example:
// Class
class Building {
// Object variables/properties
private $number_of_floors = 5; // Each building has 5 floors
private $color;
// Constructor
public function __construct($paint) {
$this->color = $paint;
}
public function describe() {
printf('This building has %d floors. It is %s in color.',
$this->number_of_floors,
$this->color
);
}
}
// Build a building and paint it red
$bldgA = new Building('red');
// Build another building and paint it blue
$bldgB = new Building('blue');
// Tell us how many floors these buildings have, and their painted color
$bldgA->describe();
$bldgB->describe();
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