使用PHP为Google图表生成JSON

Question

我正在遵循以下指南：https://developers.google.com/chart/interactive/docs/php_example

他们给出了一个json示例的json代码片段。你是怎么用php构建这个的呢？通常只需要使用json_encode()将数组转换为json，但这次似乎还需要一个对象。有人能澄清这一点吗？

json代码片段：

{
  "cols": [
    {"id":"","label":"Topping","pattern":"","type":"string"},
    {"id":"","label":"Slices","pattern":"","type":"number"}
  ],
  "rows": [
    {"c":[{"v":"Mushrooms","f":null},{"v":3,"f":null}]},
    {"c":[{"v":"Onions","f":null},{"v":1,"f":null}]},
    {"c":[{"v":"Olives","f":null},{"v":1,"f":null}]},
    {"c":[{"v":"Zucchini","f":null},{"v":1,"f":null}]},
    {"c":[{"v":"Pepperoni","f":null},{"v":2,"f":null}]}
  ]
}

到目前为止，我所拥有的：

$obj = new stdClass();
$obj->cols= array(
    array("id"=>"", "label"=>"Topping", "pattern"=>"", "type"=>"string"), 
    array("id"=>"", "label"=>"Slices", "pattern"=>"", "type"=>"string"));
$obj->rows = array(
    array()
);

echo json_encode($obj);

有没有人知道如何完成这个php表示？

编辑:我的回声输出：

{"cols":[{"id":"","label":"Topping","pattern":"","type":"string"},{"id":"","label":"Slices","pattern":"","type":"string"}],"rows":[[]]}

Answer 1

下面的代码应该可以工作：

<?php
$obj = array("cols"=>array(
    array("id"=>"", "label"=>"Topping", "pattern"=>"", "type"=>"string"), 
    array("id"=>"", "label"=>"Slices", "pattern"=>"", "type"=>"string")),
    "rows"=>array(
    array("c"=>array(array("v"=>"Mushrooms", "f"=>null), array("v"=>3, "f"=>null))),
    array("c"=>array(array("v"=>"Onions", "f"=>null), array("v"=>1, "f"=>null))),
    array("c"=>array(array("v"=>"Olives", "f"=>null), array("v"=>1, "f"=>null))),
    array("c"=>array(array("v"=>"Zucchini", "f"=>null), array("v"=>1, "f"=>null))),
    array("c"=>array(array("v"=>"Pepperoni", "f"=>null), array("v"=>2, "f"=>null))),
    )
);

echo json_encode($obj);
?>

Answer 2

PHP关联数组将转换为JSON中的对象，因此不需要stdClass。你已经得到了80%的结构，所以这里有几点建议：

$data = [
    'cols' => [],
    'rows' => [],
];

将导致：

{
    'cols': [],
    'rows': [],
}

为了获得JSON数组，不要给这些值提供键：

$data = [
    'c' => [
        [ // <- no key here
            'v' => 'Mushroom', 
            'f' => null
        ],
        [ // <- no key here
            'v' => '3', 
            'f' => null
        ],
    ],
    // ...
];

将为您提供一个数据行：

{
    "c": [ // <- we got an actual array here because there was no key
        {
            "v":"Mushrooms",
            "f":null
        },
        {
            "v":3,
            "f":null
        }
    ]
}