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  3. Introduction to Spark SQL in Python

Exercise

Aggregate dot SQL

The following code uses SQL to set the value of a dataframe called df.

df = spark.sql("""
SELECT *, 
LEAD(time,1) OVER(PARTITION BY train_id ORDER BY time) AS time_next 
FROM schedule
""")
  • The LEAD clause has an equivalent function in pyspark.sql.functions.
  • The PARTITION BY, and ORDER BY clauses each have an equivalent dot notation function that is called on the Window object.
  • The following imports are available:
    • from pyspark.sql import Window
    • from pyspark.sql.functions import lead

Instructions

100 XP
  • Create a dataframe called dot_df that contains the identical result as df, using dot notation instead of SQL.