如何解码PHP中的JSON嵌套数组值？

Question

So I have this JSON string:

"{"Jan": [5, 10, 15, 20] , 
  "Feb":[20,10,"",22], 
  "Mar":[5,3,"",4], 
  "April":[10,"",1,2]
 }, 
 {"title":"Test Chart - Month v Value"}"

I am trying to extract the data so that I can access each one so that I can iterate through the array and sequentially output the data.

The best way I can think of is to simply create an array of arrays in PHP, store key and its values together and do a nested for loop. So the array should look like this:

[[Jan, 5, 10, 15, 20],[Feb, 20, 10, ,22], [Mar, 5, 3, , 4]]

Lastly I would like to know how to store this title value into its own variable.

Answer 1

Your string isn't valid json currently, but it does contain two valid json strings. The json_decode() function won't work on your string as-is, but it does work on each individual valid json string:

<?php

// INVALID JSON STRING - THIS WON'T WORK:
$json = '{"Jan": [5, 10, 15, 20] , "Feb":[20,10,"",22], "Mar":[5,3,"",4], "April":[10,"",1,2]}, {"title":"Test Chart - Month v Value"}';
print_r(json_decode($json));

// This works:
$json = '{"Jan": [5, 10, 15, 20] , "Feb":[20,10,"",22], "Mar":[5,3,"",4], "April":[10,"",1,2]}';
print_r(json_decode($json));

// This works:
$json = '{"title":"Test Chart - Month v Value"}';
print_r(json_decode($json));

?>

Ideally you would fix the source json, but it might be getting passed to you or retrieved from a system you have no control over.

If you can safely assume that the json will always have a structure like in your example, you could split the strings out doing something like this:

if (preg_match_all("/{[^}]*}/", $str, $matches)) {
  foreach ($matches[0] AS $json) {
    print_r(json_decode($json));
  }
}

This won't work if the json object contains other objects, which is why it depends on whether you can safely assume the structure will always be the same or not.