Rename pivoted and aggregated column in PySpark Dataframe

Question

With a dataframe as follows:

from pyspark.sql.functions import avg, first

rdd = sc.parallelize(
    [
        (0, "A", 223,"201603", "PORT"), 
        (0, "A", 22,"201602", "PORT"), 
        (0, "A", 422,"201601", "DOCK"), 
        (1,"B", 3213,"201602", "DOCK"), 
        (1,"B", 3213,"201601", "PORT"), 
        (2,"C", 2321,"201601", "DOCK")
    ]
)
df_data = sqlContext.createDataFrame(rdd, ["id","type", "cost", "date", "ship"])

df_data.show()

I do a pivot on it,

df_data.groupby(df_data.id, df_data.type).pivot("date").agg(avg("cost"), first("ship")).show()

+---+----+----------------+--------------------+----------------+--------------------+----------------+--------------------+
| id|type|201601_avg(cost)|201601_first(ship)()|201602_avg(cost)|201602_first(ship)()|201603_avg(cost)|201603_first(ship)()|
+---+----+----------------+--------------------+----------------+--------------------+----------------+--------------------+
|  2|   C|          2321.0|                DOCK|            null|                null|            null|                null|
|  0|   A|           422.0|                DOCK|            22.0|                PORT|           223.0|                PORT|
|  1|   B|          3213.0|                PORT|          3213.0|                DOCK|            null|                null|
+---+----+----------------+--------------------+----------------+--------------------+----------------+--------------------+

But I get these really complicated names for the columns. Applying alias on the aggregation usually works, but because of the pivot in this case the names are even worse:

+---+----+--------------------------------------------------------------+------------------------------------------------------------------+--------------------------------------------------------------+------------------------------------------------------------------+--------------------------------------------------------------+------------------------------------------------------------------+
| id|type|201601_(avg(cost),mode=Complete,isDistinct=false) AS cost#1619|201601_(first(ship)(),mode=Complete,isDistinct=false) AS ship#1620|201602_(avg(cost),mode=Complete,isDistinct=false) AS cost#1619|201602_(first(ship)(),mode=Complete,isDistinct=false) AS ship#1620|201603_(avg(cost),mode=Complete,isDistinct=false) AS cost#1619|201603_(first(ship)(),mode=Complete,isDistinct=false) AS ship#1620|
+---+----+--------------------------------------------------------------+------------------------------------------------------------------+--------------------------------------------------------------+------------------------------------------------------------------+--------------------------------------------------------------+------------------------------------------------------------------+
|  2|   C|                                                        2321.0|                                                              DOCK|                                                          null|                                                              null|                                                          null|                                                              null|
|  0|   A|                                                         422.0|                                                              DOCK|                                                          22.0|                                                              PORT|                                                         223.0|                                                              PORT|
|  1|   B|                                                        3213.0|                                                              PORT|                                                        3213.0|                                                              DOCK|                                                          null|                                                              null|
+---+----+--------------------------------------------------------------+------------------------------------------------------------------+--------------------------------------------------------------+------------------------------------------------------------------+--------------------------------------------------------------+------------------------------------------------------------------+

Is there a way to rename the column names on the fly on the pivot and aggregation?

Asked By: Ivan

||

Source

Answer 1

A simple regular expression should do the trick:

import re

def clean_names(df):
    p = re.compile("^(w+?)_([a-z]+)((w+))(?:())?")
    return df.toDF(*[p.sub(r"1_3", c) for c in df.columns])

pivoted = df_data.groupby(...).pivot(...).agg(...)

clean_names(pivoted).printSchema()
## root
##  |-- id: long (nullable = true)
##  |-- type: string (nullable = true)
##  |-- 201601_cost: double (nullable = true)
##  |-- 201601_ship: string (nullable = true)
##  |-- 201602_cost: double (nullable = true)
##  |-- 201602_ship: string (nullable = true)
##  |-- 201603_cost: double (nullable = true)
##  |-- 201603_ship: string (nullable = true)

If you want to preserve function name you change substitution pattern to for example 1_2_3.

Answered By: zero323

Answer 2

You can alias the aggregations directly:

pivoted = df_data 
    .groupby(df_data.id, df_data.type) 
    .pivot("date") 
    .agg(
       avg('cost').alias('cost'),
       first("ship").alias('ship')
    )

pivoted.printSchema()
##root
##|-- id: long (nullable = true)
##|-- type: string (nullable = true)
##|-- 201601_cost: double (nullable = true)
##|-- 201601_ship: string (nullable = true)
##|-- 201602_cost: double (nullable = true)
##|-- 201602_ship: string (nullable = true)
##|-- 201603_cost: double (nullable = true)
##|-- 201603_ship: string (nullable = true)

Answered By: jastingo

Answer 3

A simple approach will be using alias after the aggregate function.
I start with the df_data spark dataFrame you created.

df_data.groupby(df_data.id, df_data.type).pivot("date").agg(avg("cost").alias("avg_cost"), first("ship").alias("first_ship")).show()
+---+----+---------------+-----------------+---------------+-----------------+---------------+-----------------+
| id|type|201601_avg_cost|201601_first_ship|201602_avg_cost|201602_first_ship|201603_avg_cost|201603_first_ship|
+---+----+---------------+-----------------+---------------+-----------------+---------------+-----------------+
|  1|   B|         3213.0|             PORT|         3213.0|             DOCK|           null|             null|
|  2|   C|         2321.0|             DOCK|           null|             null|           null|             null|
|  0|   A|          422.0|             DOCK|           22.0|             PORT|          223.0|             PORT|
+---+----+---------------+-----------------+---------------+-----------------+---------------+-----------------+

column names will be the form of “original_column_name_aliased_column_name”. For your case, original_column_name will be 201601, aliased_column_name will be avg_cost, and the column name is 201601_avg_cost(linked by underscore “_”).

Answered By: Frank

Answer 4

Wrote an easy and fast function to do this. Enjoy! 🙂

# This function efficiently rename pivot tables' urgly names
def rename_pivot_cols(rename_df, remove_agg):
    """change spark pivot table's default ugly column names at ease.
        Option 1: remove_agg = True: `2_sum(sum_amt)` --> `sum_amt_2`.
        Option 2: remove_agg = False: `2_sum(sum_amt)` --> `sum_sum_amt_2`
    """
    for column in rename_df.columns:
        if remove_agg == True:
            start_index = column.find('(')
            end_index = column.find(')')
            if (start_index > 0 and end_index > 0):
                rename_df = rename_df.withColumnRenamed(column, column[start_index+1:end_index]+'_'+column[:1])
        else:
            new_column = column.replace('(','_').replace(')','')
            rename_df = rename_df.withColumnRenamed(column, new_column[2:]+'_'+new_column[:1])   
    return rename_df

Answered By: Victor Z

Answer 5

Modification version from zero323 , for spark 2.4

import re

def clean_names(df):
    p = re.compile("^(w+?)_([a-z]+)((w+)(,sw+))(:sw+)?")
    return df.toDF(*[p.sub(r"1_3", c) for c in df.columns])

current column name is like 0_first(is_flashsale, false): int

Answered By: Mithril

Answer 6

You can change the name of column before pivot:

.withColumn("ship", F.concat(F.lit("ship_"), "ship"))

Answered By: DANIEL SILVA RAMOS

Rename pivoted and aggregated column in PySpark Dataframe

Question:

Answers: