根据Pyspark中另一列中的值从同一列中的另一行值中替换一行中的值？

Question

网络上存在这种变化，但与我期望的完全不一样。我有一个像这样的数据框：

     +------+-------+------------+---------------+----------------+--------+---------+
|SEQ_ID|TOOL_ID|isfleetlevel|is_golden_limit|use_golden_limit|New_UL  |New_LL   |
+------+-------+------------+---------------+----------------+--------+---------+
|790026|9160   |0           |1              |0               |26.1184 |23.2954  |
|790026|13509  |0           |0              |1               |Infinity|-Infinity|
|790026|9162   |0           |0              |0               |25.03535|23.48585 |
|790026|13510  |0           |0              |1               |Infinity|-Infinity|
|790048|9162   |0           |0              |0               |33.5    |30.5     |
|790048|13509  |0           |0              |1               |Infinity|-Infinity|
|790048|13510  |0           |0              |0               |NaN     |NaN      |
|790048|9160   |0           |1              |0               |33.94075|30.75925 |
+------+-------+------------+---------------+----------------+--------+---------+

我想将每个New_UL的New_LL和use_golden_limit值替换为is_golden_limit为1的值。因此，在这种情况下，预期结果将是：

SEQ_ID

这可能吗？

Answer 1

根据要求，每个ID仅取is_golden_limit的第一个值。

创建数据框

 +------+-------+------------+---------------+----------------+--------+---------+
|SEQ_ID|TOOL_ID|isfleetlevel|is_golden_limit|use_golden_limit|New_UL  |New_LL   |
+------+-------+------------+---------------+----------------+--------+---------+
|790026|9160   |0           |1              |0               |26.1184 |23.2954  |
|790026|13509  |0           |0              |1               |26.1184 |23.2954  |
|790026|9162   |0           |0              |0               |25.03535|23.48585 |
|790026|13510  |0           |0              |1               |26.1184 |23.2954  |
|790048|9162   |0           |0              |0               |33.5    |30.5     |
|790048|13509  |0           |0              |1               |33.94075|30.75925 |
|790048|13510  |0           |0              |0               |NaN     |NaN      |
|790048|9160   |0           |1              |0               |33.94075|30.75925 |
+------+-------+------------+---------------+----------------+--------+---------+

选择用于自连接的新数据框

并首次显示每个ID的is_golden_limit值

from pyspark.sql.window import Window
import pyspark.sql.functions as F
from pyspark.sql.types import *
import numpy as np

list=[[790026,9160,0,1,0,26.1184,23.2954],
[790026,13509,0,0,1,np.inf,-np.inf],
[790026,9162,0,0,0,25.03535,23.48585],
[790026,13510,0,0,1,np.inf,-np.inf],
[790048,9162,0,0,0,33.5,30.5],
[790048,13509,0,0,1,np.inf,-np.inf],
[790048,13510,0,0,0,np.NaN,np.NaN],
[790048,9160,0,1,0,33.94075,30.75925 ]]

df= spark.createDataFrame(list,['SEQ_ID','TOOL_ID','isfleetlevel','is_golden_limit','use_golden_limit','New_UL','New_LL'])

+------+-------+------------+---------------+----------------+--------+---------+
|SEQ_ID|TOOL_ID|isfleetlevel|is_golden_limit|use_golden_limit|  New_UL|   New_LL|
+------+-------+------------+---------------+----------------+--------+---------+
|790026|   9160|           0|              1|               0| 26.1184|  23.2954|
|790026|  13509|           0|              0|               1|Infinity|-Infinity|
|790026|   9162|           0|              0|               0|25.03535| 23.48585|
|790026|  13510|           0|              0|               1|Infinity|-Infinity|
|790048|   9162|           0|              0|               0|    33.5|     30.5|
|790048|  13509|           0|              0|               1|Infinity|-Infinity|
|790048|  13510|           0|              0|               0|     NaN|      NaN|
|790048|   9160|           0|              1|               0|33.94075| 30.75925|
+------+-------+------------+---------------+----------------+--------+---------+

根据条件加入和创建新列

df1自然会是一个较小的数据帧，因此，最佳实践是使用广播连接（将较小的数据帧广播到所有节点，以便在连接中更好地位于同一位置）。

w=Window().partitionBy("SEQ_ID").orderBy("SEQ_ID")
df1=df.select(F.col("is_golden_limit").alias("use_golden_limit"),F.col("New_UL").alias("New_UL1"),F.col("New_LL").alias("New_LL1"),"SEQ_ID").filter(F.col("is_golden_limit")==1).withColumn('row_num',F.row_number().over(w)).filter(F.col("row_num")==1).drop("row_num")

+----------------+--------+--------+------+
|use_golden_limit| New_UL1| New_LL1|SEQ_ID|
+----------------+--------+--------+------+
|               1| 26.1184| 23.2954|790026|
|               1|33.94075|30.75925|790048|
+----------------+--------+--------+------+

选择最终数据框和.show（）

df2=df.join(df1.hint("broadcast"), on=['use_golden_limit','SEQ_ID'], how='left')
df3=df2.withColumn("New_UL_Final", F.when((F.col("use_golden_limit")==1),F.col("New_UL1")).otherwise(F.col("New_UL")))\
   .withColumn("New_LL_Final", F.when((F.col("use_golden_limit")==1),F.col("New_LL1")).otherwise(F.col("New_LL")))\
   .orderBy("SEQ_ID").drop("New_UL","New_LL","New_LL1","New_UL1")

最终数据框：

df4=df3.select("SEQ_ID","TOOL_ID","isfleetlevel","is_golden_limit","use_golden_limit",F.col("New_UL_Final").alias("New_UL"),
          F.col("New_LL_Final").alias("New_LL"))
df4.show()