小编raj*_*las的帖子

我正在尝试继承 DataFrame 类并添加其他自定义方法，如下所示，以便我可以流畅地链接并确保所有方法引用相同的数据帧。我收到异常，因为列不可迭代

from pyspark.sql.dataframe import DataFrame

class Myclass(DataFrame):
def __init__(self,df):
    super().__init__(df._jdf, df.sql_ctx)

def add_column3(self):
 // Add column1 to dataframe received
  self._jdf.withColumn("col3",lit(3))
  return self

def add_column4(self):
 // Add column to dataframe received
  self._jdf.withColumn("col4",lit(4))
  return self

if __name__ == "__main__":
'''
Spark Context initialization code
col1 col2
a 1
b 2
'''
  df = spark.createDataFrame([("a",1), ("b",2)], ["col1","col2"])
  myobj = MyClass(df)
  ## Trying to accomplish below where i can chain MyClass methods & Dataframe methods
  myobj.add_column3().add_column4().drop_columns(["col1"])

'''
Expected Output
col2, col3,col4
1,3,4 …