title: How can I force a float casting on elasticsearch?
body: <p>I have an index elasticsearch with a mapping:</p>
  
  <pre><code>{
    "book": {
      "mappings": {
        "educational": {
          "properties": {
            "price": {
              "type": "float"
            },
            "title": {
              "type": "text",
              "fields": {
                "keyword": {
                  "type": "keyword",
                  "ignore_above": 256
                }
              }
            }
          }
        }
      }
    }
  }
  </code></pre>
  
  <p>Now I can index a document with instead of a float, a string:</p>
  
  <pre><code>{
    "title": "Test",
    "price": "120.99"
  }
  </code></pre>
  
  <p>The value of price will be presented as a string when I will retrieve this document later, despite the fact that the mapping say it should be a float.</p>
  
  <p>I know that the price will still be indexed as a float despite the fact that it is presented as a string but is there a way to force a casting of the field into a float to have a better coherence in the data? </p>