2017-10-10 477 views
0

我在下面有下面的代码。基本上我想要做的是从现有的值中生成一些新的列。在完成之后,我将新数据列保存为群集中的表格。对不起,我还是新手。Pyspark:使用lambda函数和.withColumn会产生无类型错误我无法理解

from pyspark.sql import SQLContext 
sqlContext = SQLContext(sc) 
from pyspark.sql.functions import udf, array 
from pyspark.sql.types import DecimalType 
import numpy as np 
import math 

df = sqlContext.sql('select * from db.mytable') 

angle_av = udf(lambda (x, y): -10 if x == 0 else math.atan2(y/x)*180/np.pi, DecimalType(20,10)) 

df = df.withColumn('a_v_angle', angle_av(array('a_v_real', 'a_v_imag'))) 

df.createOrReplaceTempView('temp') 

sqlContext.sql('create table new_table as select * from temp') 

这些操作实际上不产生任何错误。然后我试图存储DF作为一个表,并收到以下错误(我猜,因为这是时的动作的实际执行):

File "/usr/hdp/current/spark2-client/python/pyspark/worker.py", line 171, in main 
    process() 
    File "/usr/hdp/current/spark2-client/python/pyspark/worker.py", line 166, in process 
    serializer.dump_stream(func(split_index, iterator), outfile) 
    File "/usr/hdp/current/spark2-client/python/pyspark/worker.py", line 103, in <lambda> 
    func = lambda _, it: map(mapper, it) 
    File "<string>", line 1, in <lambda> 
    File "/usr/hdp/current/spark2-client/python/pyspark/worker.py", line 70, in <lambda> 
    return lambda *a: f(*a) 
    File "<stdin>", line 14, in <lambda> 
TypeError: unsupported operand type(s) for /: 'NoneType' and 'NoneType' 
    at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRDD.scala:193) 
    at org.apache.spark.api.python.PythonRunner$$anon$1.<init>(PythonRDD.scala:234) 
+0

请张贴产生错误 – desertnaut

+0

产生错误的命令的确切的命令是:sqlContext.sql( '创建NEW_TABLE如SELECT * FROM临时') –

回答

0

这是因为输入值null/None。功能应检查其输入并据此进行。

f x == 0 or x is None 

或只是

if not x 
+0

谢谢!这解决了这个问题!非常感激! –