JSON manipulation in PHP?

Question

I need to edit some data in a JSON file, and I'm looking to do so in PHP. My JSON file looks like this:

[
    {
        "field1":"data1-1",
        "field2":"data1-2"
    },
    {
        "field1":"data2-1",
        "field2":"data2-2"
    }
]

What I've done so far is $data = json_decode(file_get_contents(foo.json)) but I have no idea how to navigate this array. If for example I want to find the data from the first field of the second object, what's the PHP syntax to do so? Also, are there other ways I should know about for parsing JSON data into a PHP friendly format?

Answer 1

This JSON contains 2 arrays with 2 objects each, you can access like this:

$arr = json_decode(file_get_contents(foo.json));
// first array
echo $arr[0]->field1;
echo $arr[0]->field2;
// second array
echo $arr[1]->field1;
echo $arr[1]->field2;

if you convert this to an array and avoid objects you can then access like this:

$arr = json_decode(file_get_contents(foo.json), true);
// first array
echo $arr[0]['field1'];
echo $arr[0]['field2'];
// second array
echo $arr[1]['field1'];
echo $arr[1]['field2'];

Answer 2

$data = json_decode(file_get_contents(foo.json)); 
foreach($data as $k => &$obj) {

    $obj->field1 = 'new-data1-1';
    $obj->field2 = 'new-data1-2';

}