Impute Transform

The impute transform performs imputation of missing data objects.

Transform Parameters

Property Type Description
field Field Required. The data field for which missing values should be imputed.
key Field Required. A key field that uniquely identifies data objects within a group. Missing key values (those occuring in the data but not in the current group) will be imputed.
keyvals Any[ ] An optional array of key values that should be considered for imputation. If provided, this array will be used in addition to the key values observed within the input data.
method String The imputation method to use for the field value of imputed data objects. One of value (default), mean, median, max or min.
groupby Field[ ] An optional array of fields by which to group the values. Imputation will then be performed on a per-group basis. For example, missing values may be imputed using the group mean rather than the global mean.
value Any The field value to use when the imputation method is value.

Usage

{
  "data": [
    {
      "name": "table",
      "values": [
        {"x": 0, "y": 28, "c":0}, {"x": 0, "y": 55, "c":1},
        {"x": 1, "y": 43, "c":0}, {"x": 1, "y": 91, "c":1},
        {"x": 2, "y": 81, "c":0}, {"x": 2, "y": 53, "c":1},
        {"x": 3, "y": 19, "c":0}
      ],
      "transform": [
        {
          "type": "impute",
          "groupby": ["c"],
          "key": "x",
          "field": "y",
          "method": "value",
          "value": 500
        }
      ]
    }
  ]
}

In this example, the transform imputes the tuple

{"x": 3, "c": 1, "y": 500}