These ten questions reflect the patterns and topics that show up most frequently for https://uvik.io/ early-career candidates. Mid-level and senior questions shift toward design tradeoffs, optimization reasoning, and — increasingly in 2026 — evaluating AI-generated output. Karat tailors question difficulty and scope to role level. Karat designs its questions to be relevant, validated, and regularly rotated to prevent leakage.
A practical approach is to wrap critical code blocks in try-except statements, which allows you to catch exceptions and respond appropriately without halting the entire job. In Spark, cluster managers play a critical role in distributing resources, scheduling jobs, and ensuring efficient execution across a cluster. PySpark window functions let you perform operations across a set of rows, called a window, while returning a value for every row in the original dataset. A DAG (Directed Acyclic Graph) is the execution plan Spark builds before running a job.
A data warehouse schema defines how data entities, such as fact tables and dimension tables, are organized and related within the data warehouse system. Perform tasks like creating multidimensional views of data, aggregating information for reports, and enabling interactive data analysis. Suitable for processing small amounts of data with low processing requirements. A fact table stores quantitative data (measures or metrics) such as sales amount, quantity sold, profit, etc. For example, a time dimension table may contain year, month, day, and quarter. It is used to provide meaning to the numerical data stored in fact tables.
Python iterator implements __iter__() and the next() methods to iterate the stored elements. Iterators are used to iterate a group of elements, containers like a list. Instead, Python automatically assigns the appropriate type based on the value stored in the variable. Therefore, Python combines features of both compiled and interpreted languages. Mastering key Python interview questions is essential for succeeding in coding assessments and technical interviews for Python developer roles.
Scenario based
Be comfortable with assertions, fixtures, scopes, parametrization, temporary paths, monkeypatching, and exception tests. I pair mocks with contract or end-to-end tests based on integration risk. It should wrap only safe operations or protected idempotent writes.
- Having assessed developers’ skills, recruiters provide you with a list of viable candidates to interview and hire the most suitable one.
- This tests the understanding of how different data structures can be combined and the efficiency of operations.
- Candidates who say “I would open the trace, find the action that timed out, and check whether the network call completed” win.
- Suitable for processing small amounts of data with low processing requirements.
- For teams running large suites, the bottleneck is not the trace itself but managing thousands of trace files across runs and PRs.
- This reads the CSV, uses the first row as headers, and infers column types automatically.
You can use CSS selectors, XPath, or other selector strategies based on your needs. In Playwright, actions are the commands or functions that simulate user interactions with web applications. Once a new context is created, a browser page can be opened using the `context.newPage()` method. Opening multiple windows in Playwright can be achieved by creating additional BrowserContexts or by navigating within the same context. Playwright offers several wait actions that are crucial for ensuring the stability and reliability of automated tests.
Explain error handling best practices in production ETL pipelines.
In case the index is passed, then values of the index label will be extracted from the dictionary. This is done by using a method called issubclass() provided by python. It is created by using the pass keyword (the pass command does nothing in python). By default, the variables without prefixed underscores are public.
List comprehension offers a shorter syntax when you want to create a new list based on the values of an existing list. This prevents programs from crashing and provides a way to handle unexpected situations gracefully. Python’s exception handling system manages unexpected issues that arise while a program is running, preventing crashes and allowing for controlled error recovery.
Remember that interviewers are not just evaluating your technical skills but also your attitude, communication, and problem-solving approach. Employers often value candidates who can approach challenges methodically and adapt on the fly. Prioritize topics based on your strengths and the requirements of the data analyst roles you’re targeting.
Question 1: Bug-Fix on a Given Codebase
Use pytest.raises as a context manager, optionally matching a stable part of the message or inspecting the exception. Pytest resolves their dependency graph, runs setup according to scope, injects the value, and performs teardown for yield fixtures. A set is useful for uniqueness, membership, and set comparisons when ordering and duplicates are not part of the contract. I use None as the default and create a fresh object inside. Interviewers score the contract, correctness, readable naming, boundary coverage, complexity, and automation judgment.
