anchor.diff:  
   [[ml-put-dfanalytics-example]]
   ==== {api-examples-title}
  +
  +
  +[[ml-put-dfanalytics-example-preprocess]]
  +===== Preprocessing actions example
  +
  +The following example shows how to limit the scope of the analysis to certain 
  +fields, specify excluded fields in the destination index, and use a query to 
  +filter your data before analysis.
  +
  +[source,console]
  +--------------------------------------------------
  +PUT _ml/data_frame/analytics/model-flight-delays-pre
  +{
  +  "source": {
  +    "index": [
  +      "kibana_sample_data_flights" <1>
  +    ],
  +    "query": { <2>
  +      "range": {
  +        "DistanceKilometers": { 
  +          "gt": 0
  +        }
  +      }
  +    },
  +    "_source": { <3>
  +      "includes": [],
  +      "excludes": [
  +        "FlightDelay",
  +        "FlightDelayType"
  +      ]
  +    }
  +  },
  +  "dest": { <4>
  +    "index": "df-flight-delays",
  +    "results_field": "ml-results"
  +  },
  +  "analysis": {
  +  "regression": {
  +    "dependent_variable": "FlightDelayMin",
  +    "training_percent": 90
  +    }
  +  },
  +  "analyzed_fields": { <5>
  +    "includes": [],
  +    "excludes": [   
  +      "FlightNum"
  +    ]
  +  },
  +  "model_memory_limit": "100mb"
  +}
  +--------------------------------------------------
  +// TEST[skip:setup kibana sample data]
  +
  +<1> The source index to analyze.
  +<2> This query filters out entire documents that will not be present in the 
  +destination index.
  +<3> The `_source` object defines fields in the dataset that will be included or 
  +excluded in the destination index. In this case, `includes` does not specify any 
  +fields, so the default behavior takes place: all the fields of the source index 
  +will included except the ones that are explicitly specified in `excludes`.
  +<4> Defines the destination index that contains the results of the analysis and 
  +the fields of the source index specified in the `_source` object. Also defines 
  +the name of the `results_field`.
  +<5> Specifies fields to be included in or excluded from the analysis. This does 
  +not affect whether the fields will be present in the destination index, only 
  +affects whether they are used in the analysis.
  +
  +In this example, we can see that all the fields of the source index are included 
  +in the destination index except `FlightDelay` and `FlightDelayType` because 
  +these are defined as excluded fields by the `excludes` parameter of the 
  +`_source` object. The `FlightNum` field is included in the destination index, 
  +however it is not included in the analysis because it is explicitly specified as 
  +excluded field by the `excludes` parameter of the `analyzed_fields` object.
   
   
   [[ml-put-dfanalytics-example-od]]
  
positive.code:   that setting. For more information, see <<ml-settings>>.
    
  `source`::
    (object) The configuration of how to source the analysis data. It requires an `index`.
    Optionally, `query` and `_source` may be specified.
    
    `index`:::
      (Required, string or array) Index or indices on which to perform the 
  
negative.code:   
  `analyzed_fields`::
    (Optional, object) Specify `includes` and/or `excludes` patterns to select
    which fields will be included in the analysis. If `analyzed_fields` is not 
    set, only the relevant fields will be included. For example, all the numeric 
    fields for {oldetection}. For the supported field types, see 
    <<ml-put-dfanalytics-supported-fields>>. Also see the <<explain-dfanalytics>> 
    which helps understand field selection.
  
    `includes`:::
      (Optional, array) An array of strings that defines the fields that will be 
  