pyspark列不可迭代 [英] pyspark Column is not iterable

问题描述

当我尝试groupBy并获得max时，具有此数据帧，我无法获得Column:

Having this dataframe I am getting Column is not iterable when I try to groupBy and getting max:

linesWithSparkDF
+---+-----+
| id|cycle|
+---+-----+
| 31|   26|
| 31|   28|
| 31|   29|
| 31|   97|
| 31|   98|
| 31|  100|
| 31|  101|
| 31|  111|
| 31|  112|
| 31|  113|
+---+-----+
only showing top 10 rows


ipython-input-41-373452512490> in runlgmodel2(model, data)
     65     linesWithSparkDF.show(10)
     66 
---> 67     linesWithSparkGDF = linesWithSparkDF.groupBy(col("id")).agg(max(col("cycle")))
     68     print "linesWithSparkGDF"
     69 

/usr/hdp/current/spark-client/python/pyspark/sql/column.py in __iter__(self)
    241 
    242     def __iter__(self):
--> 243         raise TypeError("Column is not iterable")
    244 
    245     # string methods

TypeError: Column is not iterable

推荐答案

这是因为，您已经覆盖了apache-spark提供的max定义，很容易发现，因为max期望的是iterable

It's because, you've overwritten the max definition provided by apache-spark, it was easy to spot because max was expecting an iterable.

要解决此问题，您可以使用

To fix this, you can use a different syntax, and it should work.

inesWithSparkGDF = linesWithSparkDF.groupBy(col("id")).agg({"cycle": "max"})

或者

from pyspark.sql.functions import max as sparkMax

linesWithSparkGDF = linesWithSparkDF.groupBy(col("id")).agg(sparkMax(col("cycle")))

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