In this article, we are going to find the Maximum, Minimum, and Average of particular column in PySpark dataframe.
For this, we will use agg() function. This function Compute aggregates and returns the result as DataFrame.
Syntax: dataframe.agg({'column_name': 'avg/'max/min})
Where,
- dataframe is the input dataframe
- column_name is the column in the dataframe
Creating DataFrame for demonstration:
# importing module
import pyspark
# importing sparksession from pyspark.sql
# module
from pyspark.sql import SparkSession
# creating sparksession and giving an app
# name
spark = SparkSession.builder.appName('sparkdf').getOrCreate()
# list of students data
data = [["1", "sravan", "vignan", 67, 89],
["2", "ojaswi", "vvit", 78, 89],
["3", "rohith", "vvit", 100, 80],
["4", "sridevi", "vignan", 78, 80],
["1", "sravan", "vignan", 89, 98],
["5", "gnanesh", "iit", 94, 98]]
# specify column names
columns = ['student ID', 'student NAME',
'college', 'subject 1', 'subject 2']
# creating a dataframe from the lists of data
dataframe = spark.createDataFrame(data, columns)
# display dataframe
dataframe.show()
Output:
Finding Average
Example 1: Python program to find the average of dataframe column
# find average of subjects column
dataframe.agg({'subject 1': 'avg'}).show()
Output:
Example 2: Get average from multiple columns
# find average of multiple column
dataframe.agg({'subject 1': 'avg',
'student ID': 'avg',
'subject 2': 'avg'}).show()
Output:
Finding Minimum
Example 1: Python program to find the minimum value in dataframe column.
# minimum value from student ID column
dataframe.agg({'student ID': 'min'}).show()
Output:
Example 2: Get minimum value from multiple columns
# minimum value from multiple column
dataframe.agg({'college': 'min',
'student NAME': 'min',
'student ID':'min'}).show()
Output:
Finding Maximum
Example 1: Python program to find the maximum value in dataframe column
# maximum value from student ID column
dataframe.agg({'student ID': 'max'}).show()
Output:
Example 2: Get maximum value from multiple columns
# maximum value from multiple column
dataframe.agg({'college': 'max',
'student NAME': 'max',
'student ID':'max'}).show()
Output:
