PHP数组

一、认识数组

1、创建空数组

$arr = array();
var_dump( $arr );
$arrs = [];
var_dump( $arrs );

2、创建索引数组

$arr = array(
    '欧阳',
    '西门',
    '灭绝'
);
var_dump( $arr );

3、创建关联数组

$arr = [
    'ouyang' => '欧阳',
    'ximen' => '西门',
    'miejue' => '灭绝'
];
var_dump( $arr );

4、输出数组值

$arr = [
    '欧阳',
    '西门',
    '灭绝'
];
echo $arr[0];
echo '<hr>';
echo $arr[1];
echo '<hr>';
echo $arr[2];
echo '<hr>';


$arrs = [
    'ouyang' => '欧阳',
    'ximen' => '西门',
    'miejue' => '灭绝'
];
echo $arrs['ouyangke'];
echo '<hr>';
echo $arrs['huangrong'];
echo '<hr>';
echo $arrs['guojing'];
echo '<hr>';

5、打印数组print_r

$arr = [
    '欧阳',
    '西门',
    '灭绝'
];
print_r($arr);

6、php连接符

$var1 = 'PHP讲师';
$var2 = '欧阳';
var_dump( $var1 . $var2 );
var_dump( $var1 . '：' . $var2 );

二、php多维数组

1、二维数组

$arr = array(
    array(
        'name' => '欧阳',
        'school'  => 'PHP中文网'
    ),
    array(
        'name' => '西门',
        'school'  => 'PHP中文网'
    ),
    array(
        'name' => '灭绝',
        'school'  => 'PHP中文网'
    )
);
var_dump($arr);
print_r($arr);

2、三维数组

$arr = [
    [
        'name' => '欧阳',
        'school'  => 'PHP中文网',
        'gongfu' => [
            'PHP',
            '小程序',
            'layui',
            'Thinkphp'
        ]
    ],
    [
        'name' => '西门',
        'school'  => 'PHP中文网',
        'gongfu' => [
            'PHP',
            'Thinkphp',
            'Laravel',
            '实战项目'
        ]
    ],
    [
        'name' => '灭绝',
        'school'  => 'PHP中文网',
        'gongfu' => [
            'HTML',
            'PHP',
            'layui',
            'Thinkphp'
        ]
    ]
];
var_dump($arr);
print_r($arr);

备：数组最好不要超过 3 层

3、多维数组访问

$arr = [
    [
        'name' => '欧阳',
        'school'  => 'PHP中文网',
        'gongfu' => [
            'PHP',
            '小程序',
            'layui',
            'Thinkphp'
        ]
    ],
    [
        'name' => '西门',
        'school'  => 'PHP中文网',
        'gongfu' => [
            'PHP',
            'Thinkphp',
            'Laravel',
            '实战项目'
        ]
    ],
    [
        'name' => '灭绝',
        'school'  => 'PHP中文网',
        'gongfu' => [
            'HTML',
            'PHP',
            'layui',
            'Thinkphp'
        ]
    ]
];
echo $arr[0]['name'].' --- ';
echo $arr[0]['gongfu'][0].' --- ';
echo $arr[0]['gongfu'][1];

备：数组访问时，层次不要弄错

三、php数组循环

1、foreach

$arr = array(
    'ouyang' => '欧阳',
    'ximen' => '西门',
    'miejue' => '灭绝'
);
foreach( $arr as $v ){
    echo $v;
    echo '<hr>';
}

2、key和value

$k和$v变量名，可以自定义

示例1：
$arr = array[
    'ouyang' => '欧阳',
    'ximen' => '西门',
    'miejue' => '灭绝'
];
foreach( $arr as $k=>$v ){
    echo $k . ' --- ' . $v;
    echo '<hr>';
}

示例2：
$arr = [
    '欧阳',
    '西门',
    '灭绝'
];
foreach( $arr as $k=>$v ){
    echo $k . ' --- ' . $v;
    echo '<hr>';
}

3、循环多维数组

示例1：
$arr = [
    [
        'name' => '欧阳',
        'school'  => 'PHP中文网'
    ],
    [
        'name' => '西门',
        'school'  => 'PHP中文网'
    ],
    [
        'name' => '灭绝',
        'school'  => 'PHP中文网'
    ]
];
foreach( $arr as $k=>$v ){
    print_r($v);
    echo '<hr>';
}

示例2：
$arr = [
    [
        'name' => '欧阳',
        'school'  => 'PHP中文网'
    ],
    [
        'name' => '西门',
        'school'  => 'PHP中文网'
    ],
    [
        'name' => '灭绝',
        'school'  => 'PHP中文网'
    ]
];
foreach( $arr as $k=>$v ){
    foreach ($v as $key => $value) {
        echo $value;
        echo '<hr>';
    }
}

示例3：
$arr = [
    [
        'name' => '欧阳',
        'school'  => 'PHP中文网'
    ],
    [
        'name' => '西门',
        'school'  => 'PHP中文网'
    ],
    [
        'name' => '灭绝',
        'school'  => 'PHP中文网'
    ]
];
foreach( $arr as $k=>$v ){
    echo $v['name'].' --- '.$v['school'];
    echo '<hr>';
}