在Spark数据框列中获取最大值的最佳方法

>df1.show()+-----+--------------------+--------+----------+-----------+|floor|timestamp|     uid|         x|          y|+-----+--------------------+--------+----------+-----------+|    1|2014-07-19T16:00:...|600dfbe2| 103.79211|71.50419418||    1|2014-07-19T16:00:...|5e7b40e1| 110.33613|100.6828393||    1|2014-07-19T16:00:...|285d22e4|110.066315|86.48873585||    1|2014-07-19T16:00:...|74d917a1| 103.78499|71.45633073|>row1 = df1.agg({"x": "max"}).collect()[0]>print row1Row(max(x)=110.33613)>print row1["max(x)"]110.33613

答案与method3几乎相同。但似乎可以删除method3中的“ asDict（）”