The difference between single arrow and double arrow in php

The difference between single arrow and double arrow in php:

Use the -> symbol to reference the properties and methods of a class.

The following is an example applet:

<?php
//定义类Cart
class Cart {
    var $items;  // 购物车中的物品
    // 将 $num 个 $artnr 物品加入购物车
    function add_item($artnr, $num) {
        $this->items[$artnr] += $num;
    }
    // 将 $num 个 $artnr 物品从购物车中取出
    function remove_item($artnr, $num) {
        if ($this->items[$artnr] > $num) {
            $this->items[$artnr] -= $num;
            return true;
        } elseif ($this->items[$artnr] == $num) {
            unset($this->items[$artnr]);
            return true;
        } else {
            return false;
        }
    }
}
//示例继承定义类Named_Cart
class Named_Cart extends Cart {
    var $owner;
    function set_owner ($name) {
        $this->owner = $name;
    }
}
//使用类的代码
$ncart = new Named_Cart;    // 新建一个有名字的购物车
$ncart->set_owner("kris");  // 给该购物车命名
print $ncart->owner;        // 输出该购物车主人的名字
$ncart->add_item("10", 1);  // （从购物车类中继承来的功能）
?>

"->" This arrow can also be used to call a function in the class

class a { function b() { echo 'a'; } } $a=new a; $a->b(); 输出：a

=> Arrow, use to define an array:

$array1 = array('a' = >5, 'b' = >6);
while ($arrayitem = each($array1)) {
    extract($arrayitem);
    echo(&#39;<br />&#39;.$key.&#39;=&#39;.$value);
}
输出：a = 5 b = 6

Summary: PHP single arrow "->" is used to reference the attributes and methods of a class or call functions in the class. The double arrow "=>" is used to define an array.

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