如何在php中解析這個json

Question

你好，我有一個json文件即

{
   "data": [
      {
         "name": "The Lord of the Rings Trilogy (Official Page)",
         "category": "Movie"
      },
      {
         "name": "Snatch",
         "category": "Drama"
      },
      {
         "name": "The Social Network Movie",
         "category": "Movie"
      },
      {
         "name": "Scarface\u2122",
         "category": "Movie"
      }
  ]
}

我想在PHP中解析這個文件，並獲取我的PHP代碼所有類別的值

<?php
error_reporting(E_ALL);
ini_set('display_errors', true);
$string = file_get_contents("test.json");
$json_a=json_decode($string,true);
foreach ($json_a as $category_name => $category) {
    echo $category['category'];
}?>

但我得到這個錯誤

Notice: Undefined index: category in /var/www/json app/test.php on line 7

另外，我如何獲得該文件中的類別模式（模式是比任何其他模式更頻繁重復的數字），即在此示例中，“電影”是列表的模式。

Answer 1

var_dump($json_a);

在json_decode之后，您將看到該數組嵌套到data ，所以

foreach ($json_a['data'] as $category_name => $category) {
    echo $category['category'];
}

UPD

$string = '{
   "data": [
      {
         "name": "The Lord of the Rings Trilogy (Official Page)",
         "category": "Drama"
      },
      {
         "name": "Snatch",
         "category": "Movie"
      },
      {
         "name": "The Social Network Movie",
         "category": "Movie"
      },
      {
         "name": "Scarface\u2122",
         "category": "Movie"
      }
  ]
}';
$json_a=json_decode($string,true);

$categories = array();
foreach ($json_a['data'] as $category_name => $category) {
    $categories[] = $category['category'];
}

$categories_cnt = array_count_values($categories);
arsort($categories_cnt);

$categories_titles = array_keys($categories_cnt);

$most_frequent_word = reset($categories_titles);

var_dump($most_frequent_word);