将JSON导入CodeIgniter

How do I import and use JSON in CodeIgniter? For example, the codesnippet below is written in Python and converts Reddit's front page into JSON and prints the keys:

reddit_front = r"""{"kind": "Listing", "data": {"modhash": "", "children": ...  """

import json
j = json.loads(reddit_front)
print j.keys()

If you have a json string ready you can use below function in php to read json string.

$result is the json string for example

$res = json_decode($result,true);

Now use foreach to loop through the $res to print the values