数组的数据

$arr=[
        [
            'area_id' => 110000,
            'area_pid' => 0,
            'area_name' => '北京',
            'lng' => 116.405,
            'lat' => 39.905,
            'son' => [
                [
                    'area_id' => 110100,
                    'area_pid' => 110000,
                    'area_name' => '北京市',
                    'lng' => 116.405,
                    'lat' => 39.905,
                    'son' => [
                        [
                        'area_id' => 110101,
                        'area_pid' => 110100,
                        'area_name' => '东城区',
                        'lng' => 116.41,
                        'lat' => 39.9316
                        ],
                        [
                        'area_id' => 110102,
                        'area_pid' => 110100,
                        'area_name' => '西城区',
                        'lng' => 116.36,
                        'lat' => 39.9305
                        ]
                    ]
                ]
            ]
        ],
        [
        'area_id' => 120000,
        'area_pid' => 0,
        'area_name' => '天津',
        'lng' => 117.19,
        'lat' => 39.1256,
        'son' => [
            [
                'area_id' => 120100,
                'area_pid' => 120000,
                'area_name' => '天津市',
                'lng' => 117.19,
                'lat' => 39.1256,
                'son' => [
                    [
                    'area_id' => 120101,
                    'area_pid' => 120100,
                    'area_name' => '和平区',
                    'lng' => 117.215,
                    'lat' => 39.1172
                    ],
                    [
                    'area_id' => 120102,
                    'area_pid' => 120100,
                    'area_name' => '河东区',
                    'lng' => 117.226,
                    'lat' => 39.1232
                    ]
                ]
            ]
        ]
    ]
];

输出单个数据

print_r($arr[0]['son'][0]['area_name']); //输出北京市

循环出的数据

foreach ($arr as $v) {
    echo '<ul>';
    echo '<li>'.$v['area_id'].'-'.$v['area_pid'].'-'.$v['area_name'].'-'.$v['lng'].'-'.$v['lat'].'</li>';
    foreach ($v['son'] as  $v2) {
        echo '<ul><li>'.$v2['area_id'].'-'.$v2['area_pid'].'-'.$v2['area_name'].'-'.$v2['lng'].'-'.$v2['lat'].'</li></ul>';
        foreach ($v2['son'] as $v3) {
            echo '<ul><ul><li>'.$v3['area_id'].'-'.$v3['area_pid'].'-'.$v3['area_name'].'-'.$v3['lng'].'-'.$v3['lat'].'</li></ul></ul>';
        }
    }
    echo '</ul>';
    echo '<hr>';
}

输出效果

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