Helper to add pre-join computed columns

Author: cstenac

dataikuapi/dss/recipe.py

@@ -842,6 +842,14 @@ def add_virtual_input(self, input_dataset_index):
         """
         self.raw_virtual_inputs.append({"index": input_dataset_index})
 
+    def add_computed_column(self, virtual_input_index, computed_column):
+        """
+        Adds a computed column to a virtual input
+
+        Use :class:`dataikuapi.dss.utils.DSSComputedColumn` to build the computed_column object
+        """
+        self.raw_virtual_inputs[virtual_input_index]["computedColumns"].append(computed_column)
+
     def add_join(self, join_type="LEFT", input1=0, input2=1):
         """
         Adds a join between two virtual inputs. The join is initialized with no condition.

dataikuapi/dss/utils.py

@@ -41,6 +41,11 @@ def with_selected_partitions(self, ids):
         self.selection["selectedPartitions"] = ids
         return self
 
+class DSSComputedColumn(object):
+
+    @staticmethod
+    def formula(name, formula, type="double"):
+        return {"expr": formula, "mode": "GREL", "name": name, "type": type}
 
 class DSSFilterBuilder(object):
     """