i want to find exclude a particular category from the foursquare api json how can i do it in ruby?

i want to find exclude a particular category from the foursquare api json how can i do it in ruby? in case i want to exclude Amphitheater and its sub categories?

"response": {
"categories": [
  {
    "id": "4d4b7104d754a06370d81259",
    "name": "Arts & Entertainment",
    "icon": {
      "prefix": "http://ift.tt/1ttca66",
      "suffix": ".png"
    },
    "categories": [
      {
        "id": "56aa371be4b08b9a8d5734db",
        "name": "Amphitheater",
        "categories": [{
            "id": "4bf58dd8d48988d134941735",
            "name": "Dance Studio",
            categories[sub categories #edited]
            ]
      }