{
  "id": 11458,
  "title": "Dimensionality reduction",
  "url": "/competitions/avazu-ctr-prediction/discussion/11458",
  "author_name": "",
  "post_date": "2015-01-09T01:04:08.227Z",
  "votes": null,
  "comment_count": 1,
  "views": 1008,
  "content": "<p>Has anyone tried PCA for dimensionality reduction? How to determine how many principal components to choose?</p>",
  "messages": [
    {
      "id": "62477",
      "postDate": "01/09/2015 01:04:08",
      "content": "<p>Has anyone tried PCA for dimensionality reduction? How to determine how many principal components to choose?</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "62484",
      "postDate": "01/09/2015 08:19:40",
      "content": "<p>with categorial features/variables?</p>\n<p>I start to cluster features using hour... we will see :-)</p>",
      "rawMarkdown": "",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 62484,
      "author_name": "filipus",
      "author_url": "",
      "post_date": "01/09/2015 08:19:40",
      "content": "<p>with categorial features/variables?</p>\n<p>I start to cluster features using hour... we will see :-)</p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "62477": "",
    "62484": ""
  },
  "source": "meta"
}