如何在PHP中创建具有键值对的数组？

PHP为我们提供了一种特殊类型的数组，称为关联数组，它允许我们创建具有键值对的数组。创建关联数组的语法如下：

语法 1：使用 array() 构造函数

$arrayVariable = array(
    key1  => value1,
    key2 => value2,
    key3 => value3,
    ...
    keyN => valueN,
);

语法 2：使用速记符号

$arrayVariable = [
    key1  => value1,
    key2 => value2,
    key3 => value3,
    ...
    keyN => valueN,
];

笔记：

1. 最后一个键值对后面的逗号是可选的。
2. Key可以是整数或字符串类型。
3. 值可以是任何有效类型。
4. 如果Key的类型不是字符串或整数，它将根据Key的类型转换为字符串或整数。

示例 1：使用 array() 构造函数

 
"Facebook, Inc. is an online social media and
 social networking service company.",
    "Twitter" => 
"Twitter is a microblogging and social networking service on 
which users post and interact with messages known as tweets.",
    "LinkedIn" => 
"LinkedIn is a business and employment-oriented service
 that operates via websites and mobile apps.");
      
$websites["Instagram"] = "Instagram is a photo and video-sharing 
social networking service owned by Facebook, Inc.";
foreach ($websites as $key => $value) {
    echo "
$key: $value 
";
}
?>

输出：

示例 2：使用速记符号

 
"Facebook, Inc. is an online social 
    media and social networking service company.",
      
    "Twitter" => "Twitter is a microblogging and social networking service 
    on which users post and interact with messages known as tweets.",
      
    "LinkedIn" => "LinkedIn is a business and 
    employment-oriented service that operates via websites and mobile apps."];
      
$websites[
    "Instagram"] = "Instagram is a photo and video-sharing 
    social networking service owned by Facebook, Inc.";
foreach ($websites as $key => $value) {
    echo "
$key: $value 
";
}
?>

输出：