无法从PHP中的文件解码JSON

Question

I'm having troubles with json_decode in PHP:

I have this on file:

{1: ['oi','oi'], 2: ['foo','bar']}

And this is my php code:

<?php 
    $string = file_get_contents("quizen.json"); // the file
    $json = json_decode($string);
    echo $json[1][0]
?>

But the echo returns anything, I used var_dump, and I get NULL! What's the problem?

Answer 1

The issue is that your file is not valid JSON since it uses single quotes for strings and has integers as object keys:

{1: ['oi','oi'], 2: ['foo','bar']}

Also, since the JSON is an object, you should decode it to an associative array using json_decode($string, true).

According to the JSON spec:

A value can be a string in double quotes, or a number, or true or false or null, or an object or an array.

Also, the object keys need to be strings.

If you change the single quotes to double quotes and edit your PHP's decode_json call to decode to an associative array, it should work. For example:

JSON:

{"1": ["oi","oi"], "2": ["foo","bar"]}

PHP:

<?php 
    $string = file_get_contents("quizen.json"); // the file
    $json = json_decode($string, true); // set to true for associative array
    echo $json["1"][0];
?>