php数组详解，数组详解
作为一名c++程序员，在转做php开发的过程中，对php数组产生了一些混淆，与c++数组有相似的地方，也有一些不同，下面就全面地分析一下php的数组及其与c++中相应数据类型的区别和联系。
数组的分类：
1、数值数组：也叫索引数组，即以数字（从0 开始）作为数组下标。相当于C++中的vector。
2、关联数组：以字符串作为数组下标。相当于C++中的map。
3、多维数组：数组中每个元素也是一个数组。其子数组中的每个元素也可以是数组。
数组的声明：
1、数值数组
立即学习“PHP免费学习笔记（深入）”；
<span>a、如下例子中，会自动分配数字ID键。
</span><span>$names</span> = <span>array</span>("Peter","Joe","Lily"<span>);
b、如下例子中，我们人工分配数字ID键。
</span><span>$names</span>[0] = "Peter"<span>;
</span><span>$names</span>[1] = "Joe"<span>;
</span><span>$names</span>[2] = "Lily"<span>;
可以在脚本中使用这些ID键：
</span><?<span>php
</span><span>$names</span>[0] = "Peter"<span>;
</span><span>$names</span>[1] = "Joe"<span>;
</span><span>$names</span>[2] = "Lily"<span>;
</span><span>echo</span> <span>$names</span>[0]." and ".<span>$names</span>[1]." are ".<span>$names</span>[2]."'s neighbors"<span>;
</span><span>/*</span><span> 何问起 hovertree.com </span><span>*/</span>
?>
2、关联数组：
<span>例子1
</span><span>$ages</span> = <span>array</span>("Peter"=>32, "Joe"=>30, "Lily"=>28<span>);
例子2
本例与例子1相同，只是另一种创建数组的方法。
</span><span>$ages</span>["Peter"] = "32"<span>;
</span><span>$ages</span>["Joe"] = "30"<span>;
</span><span>$ages</span>["Lily"] = "28"<span>;
在脚本中使用关联数组：
</span><?<span>php
</span><span>$ages</span>["Peter"] = "32"<span>;
</span><span>$ages</span>["Joe"] = "30"<span>;
</span><span>$ages</span>["Lily"] = "28"<span>;
</span><span>echo</span> "Peter is ".<span>$ages</span>["Peter"]." years old."<span>;
</span><span>/*</span><span> 何问起 hovertree.com </span><span>*/</span>
?><span>
以上脚本输出：
Peter is </span>32 years old.
3、多维数组：
<span>在本例中，我们创建了一个带有自动分配数字ID键的多维数组：
</span><span>$families</span> = <span>array</span><span>
{
</span>"Griffin"=><span>array</span><span>
{
</span>"Peter",
"Lois",
"Megan"<span>
}</span>,
"Quagmire"=><span>array</span><span>
{
</span>"Glenn"<span>
}</span>,
"Brown"=><span>array</span><span>
{
</span>"Cleveland",
"Loretta",
"Junior"<span>
}
};
</span><span>echo</span> "Is " . <span>$families</span>['Griffin'][2] . " a part of the Griffin family?"<span>;
以上代码输出：
Is Megan a part of the Griffin family</span>?
数组遍历
1<span>、for循环遍历
for循环只能遍历索引数组。
</span><?<span>php
</span><span>$names</span> = <span>array</span>("Peter","Joe","Lily"<span>);
</span><span>for</span>(<span>$id</span>=0;<span>$id</span><<span>count</span>(<span>$names</span>);++<span>$id</span><span>)
{
</span><span>echo</span> <span>$names</span>[<span>$id</span><span>];
}
</span>?>
2<span>、foreach遍历
即可以遍历索引数组，也可以遍历关联数组
遍历索引数组
</span><span>foreach</span>(array_expression <span>as</span> <span>$value</span><span>)
{
循环体;
}
遍历关联数组
</span><span>foreach</span>(array_expression <span>as</span> <span>$key</span>=><span>$value</span><span>)
{
循环体;
}
A、一维数组遍历
索引数组
</span><?<span>php
</span><span>$contact</span> = <span>array</span>("李某","xx公司","abc@xx.com"<span>);
</span><span>foreach</span>(<span>$contact</span> <span>as</span> <span>$value</span><span>)
{
</span><span>echo</span> <span>$value</span><span>;
}
</span>?>
<?<span>php
</span><span>$contact</span> = <span>array</span>("姓名"=>"李某","公司"=>"xx公司","邮箱"=>"abc@xx.com"<span>);
</span><span>foreach</span>(<span>$contact</span> <span>as</span> <span>$key</span>=><span>$value</span><span>)
{
</span><span>echo</span> <span>$key</span>.":".<span>$value</span><span>;
}
</span>?><span>
B、多维数组遍历
</span><?<span>php
</span><span>$wage</span> = <span>array</span><span>(
</span>"市场部"=<span>array</span><span>(
</span><span>array</span>(1,"李某","市场经理",8000),
<span>array</span>(2,"王某","市场专员",5000),
<span>array</span>(3,"刘某","市场专员",7000<span>)
)</span>,
"产品部"=<span>array</span><span>(
</span><span>array</span>(1,"李某","产品经理",9000),
<span>array</span>(2,"王某","产品专员",6000),
<span>array</span>(3,"刘某","产品专员",5000<span>)
)</span>,
"账务部"=<span>array</span><span>(
</span><span>array</span>(1,"李某","账务经理",7000),
<span>array</span>(2,"王某","账务专员",6000),
<span>array</span>(3,"刘某","账务专员",5000<span>)
)
);
</span><span>foreach</span>(<span>$wage</span> <span>as</span> <span>$section</span>=><span>$table</span><span>)
{
</span><span>echo</span> <span>$section</span>."部门人员如下"<span>;
</span><span>foreach</span>(<span>$table</span> <span>as</span> <span>$row</span><span>)
{
</span><span>foreach</span>(<span>$row</span> <span>as</span> <span>$value</span><span>)
{
</span><span>echo</span> <span>$value</span><span>;
}
}
} </span><span>/*</span><span> 何问起 hovertree.com </span><span>*/</span>
?>
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