Decision Minds Data Engineer Interview Questions, Process, and Tips

Easy and moderate level question

Given a relevant topic and discussion on it

Q1. Introducd yourself
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Q2. Why do you want to join us
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Q1. Rate yourself in js, node js, react, MongoDB (separately)
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Q2. Typeof null, typeof undefined, typeof {}, typeof NaN
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Q3. What changes came in es6
Ans. 
ES6 introduced several new features and improvements to JavaScript, making it more powerful and efficient.
• Arrow functions for more concise syntax

• Let and const for block-scoped variables

• Classes for easier object-oriented programming

• Template literals for easier string interpolation

• Default parameters and rest parameters for function arguments

• Destructuring assignment for easier data extraction

• Promises for asynchronous prog
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Q4. This keyword, closures, hoisting
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Q5. Are let and cont variables hoisted?
Ans. 
Yes, let and const variables are hoisted but not initialized.
• let and const variables are hoisted to the top of their block scope, but they are not initialized until the actual line of code is executed.

• This means that you cannot access a let or const variable before it is declared in the code.

• For example, trying to access a let variable before it is declared will result in a ReferenceError.
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Q6. What is global context
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Global context refers to the overall environment or setting in which something exists or operates.
• Global context encompasses all variables, functions, and objects that are accessible throughout an entire program.

• It can be thought of as the 'big picture' view of a program's execution.

• In web development, global context includes the window object in JavaScript.
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Q7. What is temporal deadzone
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Temporal dead zone is a period during the variable creation process where accessing the variable results in a ReferenceError.
• Occurs when trying to access a variable before it has been declared with let or const

• Happens due to the variable being in the temporal dead zone until it is declared

• Example: accessing a variable before its declaration will result in a ReferenceError
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Q8. What is modules? types of modules in nodejs
Ans. 
Modules in Node.js are reusable blocks of code that encapsulate related functionality.
• Modules in Node.js can be built-in modules like fs (file system) or third-party modules like express.

• Modules help in organizing code into separate files for better maintainability and reusability.

• Modules can be imported using the require() function in Node.js.
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Q9. Index in mongodb, why we need index, is index good or bad?
Ans. 
Indexes in MongoDB improve query performance by allowing the database to quickly locate and retrieve specific documents.
• Indexes help to speed up query performance by allowing the database to quickly locate specific documents based on the indexed fields.

• Without indexes, MongoDB would have to perform a collection scan, which can be slow and resource-intensive.

• Indexes can be created on single fields or compound fields to ...read more
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Q10. What are hooks , use of useRef
Ans. 
Hooks are a feature in React that allow you to use state and other React features in functional components. useRef is a hook that allows you to create a mutable object that persists for the lifetime of the component.
• Hooks are used to add state and lifecycle methods to functional components in React

• useRef is used to create a mutable reference that persists between renders

• useRef can be used to access DOM elements directl
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Q11. Fs module, http module, worker thread?
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Q12. Why we use mongoose not mongodb driver?
Ans. 
Mongoose is an Object Data Modeling (ODM) library for MongoDB that provides a higher level of abstraction and simplifies interactions with the database.
• Mongoose provides schema validation which helps maintain data integrity.

• Mongoose simplifies querying and data manipulation with built-in functions.

• Mongoose supports middleware functions for pre and post processing of data operations.
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Q1. Difference between function and method
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Q2. A program related to strings
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Q3. A program related to prime numbers
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Q1. Tell me about projects you have worked upon
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Q2. PEP-8 standards
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Q1. Architecture of project on which you were working
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Q2. Pandas and Numpy
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Q1. Tell me your Current CTC
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Q2. Tell me your Expected CTC
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Forecasting problem - Predict daily sku level sales

Q1. What is difference between bias and variance
Ans. 
Bias is error due to overly simplistic assumptions, variance is error due to overly complex models.
• Bias is the error introduced by approximating a real-world problem, leading to underfitting.

• Variance is the error introduced by modeling the noise in the training data, leading to overfitting.

• High bias can cause a model to miss relevant relationships between features and target variable.

• High variance can cause a model to ...read more
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Q2. Parametric vs non parametruc model
Ans. 
Parametric models make strong assumptions about the form of the underlying data distribution, while non-parametric models do not.
• Parametric models have a fixed number of parameters, while non-parametric models have a flexible number of parameters.

• Parametric models are simpler and easier to interpret, while non-parametric models are more flexible and can capture complex patterns in data.

• Examples of parametric models inc...read more
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Q1. Second largest number in an array
Ans. 
Find the second largest number in an array of strings.
• Convert the strings to numbers for comparison.

• Sort the array in descending order.

• Return the second element in the sorted array.
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Q2. Pairs with given sum
Ans. 
Find pairs in an array that sum up to a given target value.
• Use a hash set to store the difference between the target value and each element in the array.

• Iterate through the array and check if the current element's complement exists in the hash set.

• Return the pairs that sum up to the target value.
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Q1. Related to Linux and Networking
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Q2. Services Samba FTP, Maintenance Mode
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Q3. Troubleshooting of Network
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Troubleshooting network involves identifying and resolving issues related to network connectivity and performance.
• Start by identifying the symptoms of the problem

• Check network cables and connections

• Verify network settings and configurations

• Use network diagnostic tools to identify and isolate the problem

• Resolve the issue by applying appropriate fixes

• Test the network to ensure the problem is resolved
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Q1. Qts related to Bootprocess AWS etc
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Q2. Port Forwarding of services
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This is the round in which basic quant questions were asked

In this round basic 2 java questions were asked

In this round one topic was given and we need to discuss about that topic

Q1. What is java explain in detail
Ans. 
Java is a high-level, object-oriented programming language used to develop applications for various platforms.
• Java is platform-independent, meaning it can run on any platform with a Java Virtual Machine (JVM)

• It is known for its security features, such as the ability to run code in a sandbox environment

• Java is used for developing a wide range of applications, from web applications to mobile apps and games

• It is also used...read more
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Q2. What is searching and sorting
Ans. 
Searching is finding a specific item in a collection of items. Sorting is arranging items in a specific order.
• Searching involves looking for a specific item in a collection of items.

• Sorting involves arranging items in a specific order, such as alphabetical or numerical.

• Searching and sorting are commonly used in computer science and data analysis.

• Examples of searching algorithms include linear search and binary search.

• E...read more
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Q1. What is binary tree explain
Ans. 
A binary tree is a data structure consisting of nodes, where each node has at most two children.
• Nodes in a binary tree have a left and/or right child node.

• The topmost node is called the root node.

• Binary trees are used in search algorithms and data compression.

• Examples of binary trees include binary search trees and heap trees.
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Q1. What is your current location
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Q2. What is your salary expectations
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