How to extract the fields using regex?

Elastic Stack Elasticsearch
9

Fyi: Since I just tested what @olof suggested here's how you would use regular expressions to extract stuff from existing fields.

Given a document in Elasticsearch that looks like this:

{
    "_index": "test",
    "_type": "tweet",
    "_id": "4",
    "_score": 1,
    "_source": {
       "date": "2014-09-16",
       "name": "John Smith",
       "tweet": "The Elasticsearch API is really easy to use",
       "user_id": 1
    }
}

You could extract the first name from the name field like this:

GET test/_search
{
   "script_fields": {
       "first_name": {
           "script": "/\\w+/.exec(_source['name'])[0]",
           "lang": "javascript"
       }
   },
   "_source": "*"
}

Install the Javascript plugin before.