Saama Technology Interview Questions

Without using built in functions like Counter , set() , or dict.get() for the core logic: Output: How it works: Iterates through each element in the lis...

• Write a script to identify repeated elements from the list and the number of times each is repeated. Without using inbuilt functions. list1 = [2, 3, 4, 3, 10, 3, 5, 6, 3, 3, 31, 10]

  Without using built in functions like Counter , set() , or dict.get() for the core logic: Output: How it works: Iterates through each element in the list. Manually checks whether the element already exists as a key in the freq dictionary by looping through existing keys. If found, increments the count; if not, adds it with count 1. Avoids dict.get() , Counter , collections , or set() as instructed. With built ins (for production code):

• Write a Scala function using Apache Spark (RDD API) to calculate the total event count on weekdays (Monday to Friday) per month from a given dataset.

  Key points: flatMap with Option : Returns Some((month, 1)) for weekdays and None for weekends, effectively filtering in a single pass. reduceByKey : Aggregates counts per month key with a shuffle. Calendar.DAY OF WEEK : Values 2–6 map to Monday–Friday. Error handling : try/catch around date parsing prevents malformed records from crashing the job. In a production setting, prefer DataFrame API with dayofweek() and date format() built in functions for better performance and readability.

• What are the differences between using the IN clause and the EXISTS clause with a VALUES table in SQL when filtering records based on a list of IDs?

  Both IN and EXISTS filter rows based on a list of values, but they differ in execution strategy, performance, and behavior with NULLs: Syntax comparison: Key differences: IN EXISTS Execution Evaluates the subquery/list fully first, then checks membership Evaluates row by row; stops as soon as a match is found (short circuits) NULL handling IN (1, NULL, 3) — if the column value is NULL, result is UNKNOWN (not TRUE/FALSE), often causing rows to disappear silently EXISTS is unaffected by NULLs in t