python - 使用python将pyspark数据框中的多列合并为一列

Question

我需要在 python 中使用 pyspark 将数据框的多列合并为一个列，并将列表(或元组)作为列的值。

Input dataframe:

+-------+-------+-------+-------+-------+
| name  |mark1  |mark2  |mark3  | Grade |
+-------+-------+-------+-------+-------+
| Jim   | 20    | 30    | 40    |  "C"  |
+-------+-------+-------+-------+-------+
| Bill  | 30    | 35    | 45    |  "A"  |
+-------+-------+-------+-------+-------+
| Kim   | 25    | 36    | 42    |  "B"  |
+-------+-------+-------+-------+-------+

Output dataframe should be

+-------+-----------------+
| name  |marks            |
+-------+-----------------+
| Jim   | [20,30,40,"C"]  |
+-------+-----------------+
| Bill  | [30,35,45,"A"]  |
+-------+-----------------+
| Kim   | [25,36,42,"B"]  |
+-------+-----------------+

Answer 1

列可以用sparks数组函数合并:

import pyspark.sql.functions as f

columns = [f.col("mark1"), ...] 

output = input.withColumn("marks", f.array(columns)).select("name", "marks")

您可能需要更改条目的类型才能使合并成功