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 occurring 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`. For example, the `mean` method will calculate the mean of all existing values within a group, and replace the missing values with the calculated mean.
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}