Comviva Technology Interview Questions and Answers

Boosting algorithms improve model accuracy by combining weak learners into a strong learner through sequential training.

• AdaBoost: Adjusts weights of misclassified instances to focus on difficult cases.

• Gradient Boosting: Optimizes a loss function by adding weak learners sequentially.

• XGBoost: An efficient implementation of gradient boosting with regularization to prevent overfitting.

• LightGBM: A gradient boosting framewor...read more

Pandas loc is label-based indexing, while iloc is integer-based indexing for selecting data in DataFrames.

• loc uses row and column labels for selection. Example: df.loc[0, 'column_name']

• iloc uses integer positions for selection. Example: df.iloc[0, 1]

• loc can accept boolean arrays for filtering. Example: df.loc[df['column_name'] > 10]

• iloc only accepts integer indices. Example: df.iloc[0:5] selects the first five rows.

This function checks if a number is prime by testing divisibility from 2 to the square root of the number.

• A prime number is greater than 1 and has no divisors other than 1 and itself.

• To check if a number n is prime, test divisibility from 2 to sqrt(n).

• If n is divisible by any number in this range, it is not prime.

• Example: 5 is prime (divisors: 1, 5), while 4 is not (divisors: 1, 2, 4).

This function calculates and prints the sum of all possible subarrays of a given list.

• A subarray is a contiguous part of an array.

• The function iterates through all possible starting points of subarrays.

• For each starting point, it calculates the sum of subarrays ending at each subsequent index.

• Example: For array [1, 2, 3], subarrays are [1], [1,2], [1,2,3], [2], [2,3], [3]. Their sums are 1, 3, 6, 2, 5, 3.

• The time compl...read more

Extract highest scores and calculate growth for students across subjects over two years.

• Use a data structure (like a DataFrame) to store student names, subjects, and scores.

• Group data by student and subject to find the maximum score for each subject.

• Example: If Student A has scores [80, 90, 85, 70, 95] in subjects [Math, Science, English, History, Art], the highest score is 95 in Art.

• For growth calculation, compare sco...read more

explode splits a string into an array, while implode joins array elements into a string.

• explode(separator, string): Splits a string by a specified separator.

• Example: explode(',', 'apple,banana,cherry') returns ['apple', 'banana', 'cherry'].

• implode(separator, array): Joins array elements into a single string with a specified separator.

• Example: implode('-', ['2023', '10', '05']) returns '2023-10-05'.

• explode is used for p...read more

I have extensive experience with PHP frameworks like Laravel and CodeIgniter, focusing on building scalable web applications.

• Proficient in Laravel for its elegant syntax and robust features like Eloquent ORM and Blade templating.

• Experience with CodeIgniter for lightweight applications, emphasizing speed and simplicity.

• Utilized Symfony components in various projects for reusable libraries and better structure.

• Implemente...read more

Use a tool like Rails migration to add a new column to the database table in production with 100 million data.

• Create a new Rails migration file to add the new column to the database table.

• Test the migration locally to ensure it works as expected.

• Deploy the migration to the production environment during a maintenance window to avoid downtime.

• Consider using tools like ActiveRecord's `change_column` method to efficiently ...read more

An application running in cloud with tightly coupled infrastructure can be deployed to on-premise by decoupling the components and using containerization.

• Decouple the application components to make them more portable

• Use containerization technologies like Docker to package the application and its dependencies

• Deploy the containerized application to on-premise servers using tools like Kubernetes for orchestration

A Business Analyst identifies needs and solutions through data analysis, stakeholder engagement, and project management.

• Identify Stakeholders: Engage with users, management, and IT to gather requirements. Example: Meeting with department heads to understand their needs.

• Gather Requirements: Use techniques like interviews, surveys, and workshops. Example: Conducting a survey to assess user satisfaction with current softw...read more