如何使用基于ID的PHP从json文件中删除对象

Question

Hi i wonder how i can delete data from json file based on id if my json struct looks like that:

[
    {
        "id": 1,
        "title": "a",
        "decription": "b"
    },
    {
        "id": 2,
        "title": "c",
        "decription": "d"
    }
]

What I've tried so far:

     if (isset($_POST['delete_post'])) 
     {

        $id = $_POST['post-id'];

        if(empty($id)) return;

        $posts = json_decode(file_get_contents('posts.json'));

        foreach ($posts as $post) 
        {
            if ($post->id == $id) 
            {
                unset ($post);
            }
            $save = json_encode($posts, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);
            file_put_contents('posts.json', $save);
        }

     }

And i literally stuck at this ponint.

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Answer 1

unset $post doesn't remove the element from the array, it just unsets that temporary variable.

After unsetting the element you need to use array_values() to get a new array with consecutive indexes. If there's a gap in the indexes, json_encode() will encode it as an object.

You also should break out of the loop once you find the element to delete and rewrite the file.

    foreach ($posts as $i => $post) 
    {
        if ($post->id == $id) 
        {
            unset ($posts[$i]);
            $save = json_encode(array_values($posts), JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);
            file_put_contents('posts.json', $save);
            break;
        }
    }