1 files changed, 48 insertions, 4 deletions
diff --git a/python/pyspark/sql/types.py b/python/pyspark/sql/types.py
index 932686e5e4..ae9344e610 100644
--- a/python/pyspark/sql/types.py
+++ b/python/pyspark/sql/types.py
@@ -355,8 +355,7 @@ class StructType(DataType):
 
     This is the data type representing a :class:`Row`.
     """
-
-    def __init__(self, fields):
+    def __init__(self, fields=None):
         """
         >>> struct1 = StructType([StructField("f1", StringType(), True)])
         >>> struct2 = StructType([StructField("f1", StringType(), True)])
@@ -368,8 +367,53 @@ class StructType(DataType):
         >>> struct1 == struct2
         False
         """
-        assert all(isinstance(f, DataType) for f in fields), "fields should be a list of DataType"
-        self.fields = fields
+        if not fields:
+            self.fields = []
+        else:
+            self.fields = fields
+            assert all(isinstance(f, StructField) for f in fields),\
+                "fields should be a list of StructField"
+
+    def add(self, field, data_type=None, nullable=True, metadata=None):
+        """
+        Construct a StructType by adding new elements to it to define the schema. The method accepts
+        either:
+            a) A single parameter which is a StructField object.
+            b) Between 2 and 4 parameters as (name, data_type, nullable (optional),
+             metadata(optional). The data_type parameter may be either a String or a DataType object
+
+        >>> struct1 = StructType().add("f1", StringType(), True).add("f2", StringType(), True, None)
+        >>> struct2 = StructType([StructField("f1", StringType(), True),\
+         StructField("f2", StringType(), True, None)])
+        >>> struct1 == struct2
+        True
+        >>> struct1 = StructType().add(StructField("f1", StringType(), True))
+        >>> struct2 = StructType([StructField("f1", StringType(), True)])
+        >>> struct1 == struct2
+        True
+        >>> struct1 = StructType().add("f1", "string", True)
+        >>> struct2 = StructType([StructField("f1", StringType(), True)])
+        >>> struct1 == struct2
+        True
+
+        :param field: Either the name of the field or a StructField object
+        :param data_type: If present, the DataType of the StructField to create
+        :param nullable: Whether the field to add should be nullable (default True)
+        :param metadata: Any additional metadata (default None)
+        :return: a new updated StructType
+        """
+        if isinstance(field, StructField):
+            self.fields.append(field)
+        else:
+            if isinstance(field, str) and data_type is None:
+                raise ValueError("Must specify DataType if passing name of struct_field to create.")
+
+            if isinstance(data_type, str):
+                data_type_f = _parse_datatype_json_value(data_type)
+            else:
+                data_type_f = data_type
+            self.fields.append(StructField(field, data_type_f, nullable, metadata))
+        return self
 
     def simpleString(self):
         return 'struct<%s>' % (','.join(f.simpleString() for f in self.fields))