The average of the values is calculated by adding the values and dividing by the number of values.

The avg API has several implementations, as follows. The exact API used depends on the specific use case:

def avg(columnName: String): Column
Aggregate function: returns the average of the values in a group.

def avg(e: Column): Column
Aggregate function: returns the average of the values in a group.

Let's look at an example of invoking avg on the DataFrame to print the average population:

import org.apache.spark.sql.functions._
scala> statesPopulationDF.select(avg("Population")).show
+-----------------+
| avg(Population)|
+-----------------+
|6253399.371428572|
+-----------------+