โจ๏ธ MongoDB Cheat Sheet
This Post includes a MongoDB cheat sheet to make it easy for our followers to work with MongoDB.
Working with databases
Working with rows
Working with Documents
Querying data from documents
Modifying data in documents
Searching
MongoDB is a flexible, document-orientated, NoSQL database program that can scale to any enterprise volume without compromising search performance.
This Post includes a MongoDB cheat sheet to make it easy for our followers to work with MongoDB.
Working with databases
Working with rows
Working with Documents
Querying data from documents
Modifying data in documents
Searching
โค1
๐ฐ C++ Roadmap for Beginners 2025
โโโ ๐ง Introduction to C++ & How It Works
โโโ ๐งฐ Setting Up Environment (IDE, Compiler)
โโโ ๐ Basic Syntax & Structure
โโโ ๐ข Variables, Data Types & Constants
โโโ โ Operators (Arithmetic, Relational, Logical, Bitwise)
โโโ ๐ Flow Control (if, else, switch)
โโโ ๐ Loops (for, while, do...while)
โโโ ๐งฉ Functions (Declaration, Definition, Recursion)
โโโ ๐ฆ Arrays, Strings & Vectors
โโโ ๐งฑ Pointers & References
โโโ ๐งฎ Dynamic Memory Allocation (new, delete)
โโโ ๐ Structures & Unions
โโโ ๐ Object-Oriented Programming (Classes, Objects, Inheritance, Polymorphism)
โโโ ๐ File Handling in C++
โโโ โ ๏ธ Exception Handling
โโโ ๐ง STL (Standard Template Library - vector, map, set, etc.)
โโโ ๐งช Mini Projects (Bank System, Student Record, etc.)
Like for the detailed explanation โค๏ธ
#c #programming
โโโ ๐ง Introduction to C++ & How It Works
โโโ ๐งฐ Setting Up Environment (IDE, Compiler)
โโโ ๐ Basic Syntax & Structure
โโโ ๐ข Variables, Data Types & Constants
โโโ โ Operators (Arithmetic, Relational, Logical, Bitwise)
โโโ ๐ Flow Control (if, else, switch)
โโโ ๐ Loops (for, while, do...while)
โโโ ๐งฉ Functions (Declaration, Definition, Recursion)
โโโ ๐ฆ Arrays, Strings & Vectors
โโโ ๐งฑ Pointers & References
โโโ ๐งฎ Dynamic Memory Allocation (new, delete)
โโโ ๐ Structures & Unions
โโโ ๐ Object-Oriented Programming (Classes, Objects, Inheritance, Polymorphism)
โโโ ๐ File Handling in C++
โโโ โ ๏ธ Exception Handling
โโโ ๐ง STL (Standard Template Library - vector, map, set, etc.)
โโโ ๐งช Mini Projects (Bank System, Student Record, etc.)
Like for the detailed explanation โค๏ธ
#c #programming
โค3
App Development Roadmap (2025)
Step-1 Plan Your Idea โ Define the app's purpose, features, and target audience.
Step-2 Learn Programming Basics โ Start with Python, Java, Swift, or Kotlin.
Step-3 Design UI/UX โ Create wireframes using tools like Figma or Adobe XD.
Step-4 Frontend Development โ Learn HTML, CSS, and JavaScript for web apps.
Step-5 Backend Development โ Master server-side languages (e.g., Python with Flask/Django or Node.js).
Step-6 APIs โ Integrate APIs to add functionality (e.g., payments, maps).
Step-7 Databases โ Work with SQL (MySQL/PostgreSQL) or NoSQL (MongoDB).
Step-8 Mobile Development โ Learn Swift for iOS or Kotlin for Android apps.
Step-9 Cross-Platform Tools โ Explore Flutter or React Native for both iOS and Android.
Step-10 Testing โ Perform unit & integration testing.
Step-11 Deployment โ Publish apps on app stores or deploy web apps to platforms like AWS/Heroku.
๐ Start Developing Apps Today! ๐
Step-1 Plan Your Idea โ Define the app's purpose, features, and target audience.
Step-2 Learn Programming Basics โ Start with Python, Java, Swift, or Kotlin.
Step-3 Design UI/UX โ Create wireframes using tools like Figma or Adobe XD.
Step-4 Frontend Development โ Learn HTML, CSS, and JavaScript for web apps.
Step-5 Backend Development โ Master server-side languages (e.g., Python with Flask/Django or Node.js).
Step-6 APIs โ Integrate APIs to add functionality (e.g., payments, maps).
Step-7 Databases โ Work with SQL (MySQL/PostgreSQL) or NoSQL (MongoDB).
Step-8 Mobile Development โ Learn Swift for iOS or Kotlin for Android apps.
Step-9 Cross-Platform Tools โ Explore Flutter or React Native for both iOS and Android.
Step-10 Testing โ Perform unit & integration testing.
Step-11 Deployment โ Publish apps on app stores or deploy web apps to platforms like AWS/Heroku.
๐ Start Developing Apps Today! ๐
โค3
Common Programming Interview Questions
How do you reverse a string?
How do you determine if a string is a palindrome?
How do you calculate the number of numerical digits in a string?
How do you find the count for the occurrence of a particular character in a string?
How do you find the non-matching characters in a string?
How do you find out if the two given strings are anagrams?
How do you calculate the number of vowels and consonants in a string?
How do you total all of the matching integer elements in an array?
How do you reverse an array?
How do you find the maximum element in an array?
How do you sort an array of integers in ascending order?
How do you print a Fibonacci sequence using recursion?
How do you calculate the sum of two integers?
How do you find the average of numbers in a list?
How do you check if an integer is even or odd?
How do you find the middle element of a linked list?
How do you remove a loop in a linked list?
How do you merge two sorted linked lists?
How do you implement binary search to find an element in a sorted array?
How do you print a binary tree in vertical order?
Conceptual Coding Interview Questions
What is a data structure?
What is an array?
What is a linked list?
What is the difference between an array and a linked list?
What is LIFO?
What is FIFO?
What is a stack?
What are binary trees?
What are binary search trees?
What is object-oriented programming?
What is the purpose of a loop in programming?
What is a conditional statement?
What is debugging?
What is recursion?
What are the differences between linear and non-linear data structures?
General Coding Interview Questions
What programming languages do you have experience working with?
Describe a time you faced a challenge in a project you were working on and how you overcame it.
Walk me through a project youโre currently or have recently worked on.
Give an example of a project you worked on where you had to learn a new programming language or technology. How did you go about learning it?
How do you ensure your code is readable by other developers?
What are your interests outside of programming?
How do you keep your skills sharp and up to date?
How do you collaborate on projects with non-technical team members?
Tell me about a time when you had to explain a complex technical concept to a non-technical team member.
How do you get started on a new coding project?
Best Programming Resources: https://topmate.io/coding/886839
Join for more: https://t.me/programming_guide
ENJOY LEARNING ๐๐
How do you reverse a string?
How do you determine if a string is a palindrome?
How do you calculate the number of numerical digits in a string?
How do you find the count for the occurrence of a particular character in a string?
How do you find the non-matching characters in a string?
How do you find out if the two given strings are anagrams?
How do you calculate the number of vowels and consonants in a string?
How do you total all of the matching integer elements in an array?
How do you reverse an array?
How do you find the maximum element in an array?
How do you sort an array of integers in ascending order?
How do you print a Fibonacci sequence using recursion?
How do you calculate the sum of two integers?
How do you find the average of numbers in a list?
How do you check if an integer is even or odd?
How do you find the middle element of a linked list?
How do you remove a loop in a linked list?
How do you merge two sorted linked lists?
How do you implement binary search to find an element in a sorted array?
How do you print a binary tree in vertical order?
Conceptual Coding Interview Questions
What is a data structure?
What is an array?
What is a linked list?
What is the difference between an array and a linked list?
What is LIFO?
What is FIFO?
What is a stack?
What are binary trees?
What are binary search trees?
What is object-oriented programming?
What is the purpose of a loop in programming?
What is a conditional statement?
What is debugging?
What is recursion?
What are the differences between linear and non-linear data structures?
General Coding Interview Questions
What programming languages do you have experience working with?
Describe a time you faced a challenge in a project you were working on and how you overcame it.
Walk me through a project youโre currently or have recently worked on.
Give an example of a project you worked on where you had to learn a new programming language or technology. How did you go about learning it?
How do you ensure your code is readable by other developers?
What are your interests outside of programming?
How do you keep your skills sharp and up to date?
How do you collaborate on projects with non-technical team members?
Tell me about a time when you had to explain a complex technical concept to a non-technical team member.
How do you get started on a new coding project?
Best Programming Resources: https://topmate.io/coding/886839
Join for more: https://t.me/programming_guide
ENJOY LEARNING ๐๐
โค1๐ฅ1
๐๐๐ญ๐ ๐๐ง๐๐ฅ๐ฒ๐ฌ๐ญ ๐ฏ๐ฌ. ๐๐๐ญ๐ ๐๐๐ข๐๐ง๐ญ๐ข๐ฌ๐ญ โ ๐๐ก๐๐ญโ๐ฌ ๐ญ๐ก๐ ๐๐ข๐๐๐๐ซ๐๐ง๐๐?
Whether you're starting a career in data or looking to pivot, itโs crucial to understand the key differences between a Data Analyst and a Data Scientist:
๐ ๐ ๐จ๐๐ฎ๐ฌ
Data Analyst: Interprets existing data to uncover insights.
Data Scientist: Predicts future trends using advanced models.
๐ ๏ธ ๐๐จ๐จ๐ฅ๐ฌ ๐๐ฌ๐๐
Data Analyst: Excel, SQL, Tableau
Data Scientist: Python, R, Machine Learning tools
๐ผ ๐๐ฒ๐ฉ๐ ๐จ๐ ๐๐จ๐ซ๐ค
Data Analyst: Reporting and dashboarding
Data Scientist: Building models and algorithms
๐ง ๐๐ค๐ข๐ฅ๐ฅ๐ฌ๐๐ญ
Data Analyst: Data cleaning, visualization
Data Scientist: Data-driven product development and strategy
Both roles are essentialโbut they serve different purposes. One tells you what happened, the other helps you decide what to do next.
Whether you're starting a career in data or looking to pivot, itโs crucial to understand the key differences between a Data Analyst and a Data Scientist:
๐ ๐ ๐จ๐๐ฎ๐ฌ
Data Analyst: Interprets existing data to uncover insights.
Data Scientist: Predicts future trends using advanced models.
๐ ๏ธ ๐๐จ๐จ๐ฅ๐ฌ ๐๐ฌ๐๐
Data Analyst: Excel, SQL, Tableau
Data Scientist: Python, R, Machine Learning tools
๐ผ ๐๐ฒ๐ฉ๐ ๐จ๐ ๐๐จ๐ซ๐ค
Data Analyst: Reporting and dashboarding
Data Scientist: Building models and algorithms
๐ง ๐๐ค๐ข๐ฅ๐ฅ๐ฌ๐๐ญ
Data Analyst: Data cleaning, visualization
Data Scientist: Data-driven product development and strategy
Both roles are essentialโbut they serve different purposes. One tells you what happened, the other helps you decide what to do next.
โค1
Launch Your Career in Data Analytics, Data Science & AI ๐
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Eligibility: BTech / BCA / BSc / BBA / BA / BCom
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Limited Seats โ Secure Yours Now๐
๐ https://go.acciojob.com/RYFvdU
Learn Live from Top Data Experts at Leading Tech Companies!
Master in-demand skills and land your dream job in Data Science, Analytics, or AI with expert-led live training.
Eligibility: BTech / BCA / BSc / BBA / BA / BCom
๐น 2000+ Students Placed
๐น 500+ Hiring Partners
๐น โน7.4 LPA Average Package
๐น โน41 LPA Highest Package
Limited Seats โ Secure Yours Now๐
๐ https://go.acciojob.com/RYFvdU
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โค2
Master Javascript :
The JavaScript Tree ๐
|
|โโ Variables
| โโโ var
| โโโ let
| โโโ const
|
|โโ Data Types
| โโโ String
| โโโ Number
| โโโ Boolean
| โโโ Object
| โโโ Array
| โโโ Null
| โโโ Undefined
|
|โโ Operators
| โโโ Arithmetic
| โโโ Assignment
| โโโ Comparison
| โโโ Logical
| โโโ Unary
| โโโ Ternary (Conditional)
||โโ Control Flow
| โโโ if statement
| โโโ else statement
| โโโ else if statement
| โโโ switch statement
| โโโ for loop
| โโโ while loop
| โโโ do-while loop
|
|โโ Functions
| โโโ Function declaration
| โโโ Function expression
| โโโ Arrow function
| โโโ IIFE (Immediately Invoked Function Expression)
|
|โโ Scope
| โโโ Global scope
| โโโ Local scope
| โโโ Block scope
| โโโ Lexical scope
||โโ Arrays
| โโโ Array methods
| | โโโ push()
| | โโโ pop()
| | โโโ shift()
| | โโโ unshift()
| | โโโ splice()
| | โโโ slice()
| | โโโ concat()
| โโโ Array iteration
| โโโ forEach()
| โโโ map()
| โโโ filter()
| โโโ reduce()|
|โโ Objects
| โโโ Object properties
| | โโโ Dot notation
| | โโโ Bracket notation
| โโโ Object methods
| | โโโ Object.keys()
| | โโโ Object.values()
| | โโโ Object.entries()
| โโโ Object destructuring
||โโ Promises
| โโโ Promise states
| | โโโ Pending
| | โโโ Fulfilled
| | โโโ Rejected
| โโโ Promise methods
| | โโโ then()
| | โโโ catch()
| | โโโ finally()
| โโโ Promise.all()
|
|โโ Asynchronous JavaScript
| โโโ Callbacks
| โโโ Promises
| โโโ Async/Await
|
|โโ Error Handling
| โโโ try...catch statement
| โโโ throw statement
|
|โโ JSON (JavaScript Object Notation)
||โโ Modules
| โโโ import
| โโโ export
|
|โโ DOM Manipulation
| โโโ Selecting elements
| โโโ Modifying elements
| โโโ Creating elements
|
|โโ Events
| โโโ Event listeners
| โโโ Event propagation
| โโโ Event delegation
|
|โโ AJAX (Asynchronous JavaScript and XML)
|
|โโ Fetch API
||โโ ES6+ Features
| โโโ Template literals
| โโโ Destructuring assignment
| โโโ Spread/rest operator
| โโโ Arrow functions
| โโโ Classes
| โโโ let and const
| โโโ Default parameters
| โโโ Modules
| โโโ Promises
|
|โโ Web APIs
| โโโ Local Storage
| โโโ Session Storage
| โโโ Web Storage API
|
|โโ Libraries and Frameworks
| โโโ React
| โโโ Angular
| โโโ Vue.js
||โโ Debugging
| โโโ Console.log()
| โโโ Breakpoints
| โโโ DevTools
|
|โโ Others
| โโโ Closures
| โโโ Callbacks
| โโโ Prototypes
| โโโ this keyword
| โโโ Hoisting
| โโโ Strict mode
|
| END __
The JavaScript Tree ๐
|
|โโ Variables
| โโโ var
| โโโ let
| โโโ const
|
|โโ Data Types
| โโโ String
| โโโ Number
| โโโ Boolean
| โโโ Object
| โโโ Array
| โโโ Null
| โโโ Undefined
|
|โโ Operators
| โโโ Arithmetic
| โโโ Assignment
| โโโ Comparison
| โโโ Logical
| โโโ Unary
| โโโ Ternary (Conditional)
||โโ Control Flow
| โโโ if statement
| โโโ else statement
| โโโ else if statement
| โโโ switch statement
| โโโ for loop
| โโโ while loop
| โโโ do-while loop
|
|โโ Functions
| โโโ Function declaration
| โโโ Function expression
| โโโ Arrow function
| โโโ IIFE (Immediately Invoked Function Expression)
|
|โโ Scope
| โโโ Global scope
| โโโ Local scope
| โโโ Block scope
| โโโ Lexical scope
||โโ Arrays
| โโโ Array methods
| | โโโ push()
| | โโโ pop()
| | โโโ shift()
| | โโโ unshift()
| | โโโ splice()
| | โโโ slice()
| | โโโ concat()
| โโโ Array iteration
| โโโ forEach()
| โโโ map()
| โโโ filter()
| โโโ reduce()|
|โโ Objects
| โโโ Object properties
| | โโโ Dot notation
| | โโโ Bracket notation
| โโโ Object methods
| | โโโ Object.keys()
| | โโโ Object.values()
| | โโโ Object.entries()
| โโโ Object destructuring
||โโ Promises
| โโโ Promise states
| | โโโ Pending
| | โโโ Fulfilled
| | โโโ Rejected
| โโโ Promise methods
| | โโโ then()
| | โโโ catch()
| | โโโ finally()
| โโโ Promise.all()
|
|โโ Asynchronous JavaScript
| โโโ Callbacks
| โโโ Promises
| โโโ Async/Await
|
|โโ Error Handling
| โโโ try...catch statement
| โโโ throw statement
|
|โโ JSON (JavaScript Object Notation)
||โโ Modules
| โโโ import
| โโโ export
|
|โโ DOM Manipulation
| โโโ Selecting elements
| โโโ Modifying elements
| โโโ Creating elements
|
|โโ Events
| โโโ Event listeners
| โโโ Event propagation
| โโโ Event delegation
|
|โโ AJAX (Asynchronous JavaScript and XML)
|
|โโ Fetch API
||โโ ES6+ Features
| โโโ Template literals
| โโโ Destructuring assignment
| โโโ Spread/rest operator
| โโโ Arrow functions
| โโโ Classes
| โโโ let and const
| โโโ Default parameters
| โโโ Modules
| โโโ Promises
|
|โโ Web APIs
| โโโ Local Storage
| โโโ Session Storage
| โโโ Web Storage API
|
|โโ Libraries and Frameworks
| โโโ React
| โโโ Angular
| โโโ Vue.js
||โโ Debugging
| โโโ Console.log()
| โโโ Breakpoints
| โโโ DevTools
|
|โโ Others
| โโโ Closures
| โโโ Callbacks
| โโโ Prototypes
| โโโ this keyword
| โโโ Hoisting
| โโโ Strict mode
|
| END __
โค5
Important questions to ace your machine learning interview with an approach to answer:
1. Machine Learning Project Lifecycle:
- Define the problem
- Gather and preprocess data
- Choose a model and train it
- Evaluate model performance
- Tune and optimize the model
- Deploy and maintain the model
2. Supervised vs Unsupervised Learning:
- Supervised Learning: Uses labeled data for training (e.g., predicting house prices from features).
- Unsupervised Learning: Uses unlabeled data to find patterns or groupings (e.g., clustering customer segments).
3. Evaluation Metrics for Regression:
- Mean Absolute Error (MAE)
- Mean Squared Error (MSE)
- Root Mean Squared Error (RMSE)
- R-squared (coefficient of determination)
4. Overfitting and Prevention:
- Overfitting: Model learns the noise instead of the underlying pattern.
- Prevention: Use simpler models, cross-validation, regularization.
5. Bias-Variance Tradeoff:
- Balancing error due to bias (underfitting) and variance (overfitting) to find an optimal model complexity.
6. Cross-Validation:
- Technique to assess model performance by splitting data into multiple subsets for training and validation.
7. Feature Selection Techniques:
- Filter methods (e.g., correlation analysis)
- Wrapper methods (e.g., recursive feature elimination)
- Embedded methods (e.g., Lasso regularization)
8. Assumptions of Linear Regression:
- Linearity
- Independence of errors
- Homoscedasticity (constant variance)
- No multicollinearity
9. Regularization in Linear Models:
- Adds a penalty term to the loss function to prevent overfitting by shrinking coefficients.
10. Classification vs Regression:
- Classification: Predicts a categorical outcome (e.g., class labels).
- Regression: Predicts a continuous numerical outcome (e.g., house price).
11. Dimensionality Reduction Algorithms:
- Principal Component Analysis (PCA)
- t-Distributed Stochastic Neighbor Embedding (t-SNE)
12. Decision Tree:
- Tree-like model where internal nodes represent features, branches represent decisions, and leaf nodes represent outcomes.
13. Ensemble Methods:
- Combine predictions from multiple models to improve accuracy (e.g., Random Forest, Gradient Boosting).
14. Handling Missing or Corrupted Data:
- Imputation (e.g., mean substitution)
- Removing rows or columns with missing data
- Using algorithms robust to missing values
15. Kernels in Support Vector Machines (SVM):
- Linear kernel
- Polynomial kernel
- Radial Basis Function (RBF) kernel
Data Science Interview Resources
๐๐
https://topmate.io/coding/914624
Like for more ๐
1. Machine Learning Project Lifecycle:
- Define the problem
- Gather and preprocess data
- Choose a model and train it
- Evaluate model performance
- Tune and optimize the model
- Deploy and maintain the model
2. Supervised vs Unsupervised Learning:
- Supervised Learning: Uses labeled data for training (e.g., predicting house prices from features).
- Unsupervised Learning: Uses unlabeled data to find patterns or groupings (e.g., clustering customer segments).
3. Evaluation Metrics for Regression:
- Mean Absolute Error (MAE)
- Mean Squared Error (MSE)
- Root Mean Squared Error (RMSE)
- R-squared (coefficient of determination)
4. Overfitting and Prevention:
- Overfitting: Model learns the noise instead of the underlying pattern.
- Prevention: Use simpler models, cross-validation, regularization.
5. Bias-Variance Tradeoff:
- Balancing error due to bias (underfitting) and variance (overfitting) to find an optimal model complexity.
6. Cross-Validation:
- Technique to assess model performance by splitting data into multiple subsets for training and validation.
7. Feature Selection Techniques:
- Filter methods (e.g., correlation analysis)
- Wrapper methods (e.g., recursive feature elimination)
- Embedded methods (e.g., Lasso regularization)
8. Assumptions of Linear Regression:
- Linearity
- Independence of errors
- Homoscedasticity (constant variance)
- No multicollinearity
9. Regularization in Linear Models:
- Adds a penalty term to the loss function to prevent overfitting by shrinking coefficients.
10. Classification vs Regression:
- Classification: Predicts a categorical outcome (e.g., class labels).
- Regression: Predicts a continuous numerical outcome (e.g., house price).
11. Dimensionality Reduction Algorithms:
- Principal Component Analysis (PCA)
- t-Distributed Stochastic Neighbor Embedding (t-SNE)
12. Decision Tree:
- Tree-like model where internal nodes represent features, branches represent decisions, and leaf nodes represent outcomes.
13. Ensemble Methods:
- Combine predictions from multiple models to improve accuracy (e.g., Random Forest, Gradient Boosting).
14. Handling Missing or Corrupted Data:
- Imputation (e.g., mean substitution)
- Removing rows or columns with missing data
- Using algorithms robust to missing values
15. Kernels in Support Vector Machines (SVM):
- Linear kernel
- Polynomial kernel
- Radial Basis Function (RBF) kernel
Data Science Interview Resources
๐๐
https://topmate.io/coding/914624
Like for more ๐
โค2
๐๐ข๐๐ซ๐จ๐ฌ๐จ๐๐ญ ๐
๐๐๐ ๐๐๐ซ๐ญ๐ข๐๐ข๐๐๐ญ๐ข๐จ๐ง ๐๐จ๐ฎ๐ซ๐ฌ๐๐ฌ!๐๐ป
Supercharge your career with 5 FREE Microsoft certification courses designed to boost your data analytics skills!
๐๐ง๐ซ๐จ๐ฅ๐ฅ ๐ ๐จ๐ซ ๐ ๐๐๐๐ :-
https://bit.ly/3Vlixcq
- Earn certifications to showcase your skills
Donโt waitโstart your journey to success today! โจ
Supercharge your career with 5 FREE Microsoft certification courses designed to boost your data analytics skills!
๐๐ง๐ซ๐จ๐ฅ๐ฅ ๐ ๐จ๐ซ ๐ ๐๐๐๐ :-
https://bit.ly/3Vlixcq
- Earn certifications to showcase your skills
Donโt waitโstart your journey to success today! โจ
โค4
Tips for solving leetcode codings interview problems
If input array is sorted then
- Binary search
- Two pointers
If asked for all permutations/subsets then
- Backtracking
If given a tree then
- DFS
- BFS
If given a graph then
- DFS
- BFS
If given a linked list then
- Two pointers
If recursion is banned then
- Stack
If must solve in-place then
- Swap corresponding values
- Store one or more different values in the same pointer
If asked for maximum/minimum subarray/subset/options then
- Dynamic programming
If asked for top/least K items then
- Heap
If asked for common strings then
- Map
- Trie
Else
- Map/Set for O(1) time & O(n) space
- Sort input for O(nlogn) time and O(1) space
If input array is sorted then
- Binary search
- Two pointers
If asked for all permutations/subsets then
- Backtracking
If given a tree then
- DFS
- BFS
If given a graph then
- DFS
- BFS
If given a linked list then
- Two pointers
If recursion is banned then
- Stack
If must solve in-place then
- Swap corresponding values
- Store one or more different values in the same pointer
If asked for maximum/minimum subarray/subset/options then
- Dynamic programming
If asked for top/least K items then
- Heap
If asked for common strings then
- Map
- Trie
Else
- Map/Set for O(1) time & O(n) space
- Sort input for O(nlogn) time and O(1) space
โค4
Top free Data Science resources
1. CS109 Data Science
http://cs109.github.io/2015/pages/videos.html
2. Machine Learning with Python
https://www.freecodecamp.org/learn/machine-learning-with-python/
3. Learning From Data from California Institute of Technology
http://work.caltech.edu/telecourse
4. Mathematics for Machine Learning by University of California, Berkeley
https://gwthomas.github.io/docs/math4ml.pdf?fbclid=IwAR2UsBgZW9MRgS3nEo8Zh_ukUFnwtFeQS8Ek3OjGxZtDa7UxTYgIs_9pzSI
5. Foundations of Data Science by Avrim Blum, John Hopcroft, and Ravindran Kannan
https://www.cs.cornell.edu/jeh/book.pdf?fbclid=IwAR19tDrnNh8OxAU1S-tPklL1mqj-51J1EJUHmcHIu2y6yEv5ugrWmySI2WY
6. Python Data Science Handbook
https://jakevdp.github.io/PythonDataScienceHandbook/?fbclid=IwAR34IRk2_zZ0ht7-8w5rz13N6RP54PqjarQw1PTpbMqKnewcwRy0oJ-Q4aM
7. CS 221 โ Artificial Intelligence
https://stanford.edu/~shervine/teaching/cs-221/
8. Ten Lectures and Forty-Two Open Problems in the Mathematics of Data Science
https://ocw.mit.edu/courses/mathematics/18-s096-topics-in-mathematics-of-data-science-fall-2015/lecture-notes/MIT18_S096F15_TenLec.pdf
9. Python for Data Analysis by Boston University
https://www.bu.edu/tech/files/2017/09/Python-for-Data-Analysis.pptx
10. Data Mining bu University of Buffalo
https://cedar.buffalo.edu/~srihari/CSE626/index.html?fbclid=IwAR3XZ50uSZAb3u5BP1Qz68x13_xNEH8EdEBQC9tmGEp1BoxLNpZuBCtfMSE
Credits: https://whatsapp.com/channel/0029VaxbzNFCxoAmYgiGTL3Z
1. CS109 Data Science
http://cs109.github.io/2015/pages/videos.html
2. Machine Learning with Python
https://www.freecodecamp.org/learn/machine-learning-with-python/
3. Learning From Data from California Institute of Technology
http://work.caltech.edu/telecourse
4. Mathematics for Machine Learning by University of California, Berkeley
https://gwthomas.github.io/docs/math4ml.pdf?fbclid=IwAR2UsBgZW9MRgS3nEo8Zh_ukUFnwtFeQS8Ek3OjGxZtDa7UxTYgIs_9pzSI
5. Foundations of Data Science by Avrim Blum, John Hopcroft, and Ravindran Kannan
https://www.cs.cornell.edu/jeh/book.pdf?fbclid=IwAR19tDrnNh8OxAU1S-tPklL1mqj-51J1EJUHmcHIu2y6yEv5ugrWmySI2WY
6. Python Data Science Handbook
https://jakevdp.github.io/PythonDataScienceHandbook/?fbclid=IwAR34IRk2_zZ0ht7-8w5rz13N6RP54PqjarQw1PTpbMqKnewcwRy0oJ-Q4aM
7. CS 221 โ Artificial Intelligence
https://stanford.edu/~shervine/teaching/cs-221/
8. Ten Lectures and Forty-Two Open Problems in the Mathematics of Data Science
https://ocw.mit.edu/courses/mathematics/18-s096-topics-in-mathematics-of-data-science-fall-2015/lecture-notes/MIT18_S096F15_TenLec.pdf
9. Python for Data Analysis by Boston University
https://www.bu.edu/tech/files/2017/09/Python-for-Data-Analysis.pptx
10. Data Mining bu University of Buffalo
https://cedar.buffalo.edu/~srihari/CSE626/index.html?fbclid=IwAR3XZ50uSZAb3u5BP1Qz68x13_xNEH8EdEBQC9tmGEp1BoxLNpZuBCtfMSE
Credits: https://whatsapp.com/channel/0029VaxbzNFCxoAmYgiGTL3Z
โค2
Hey guys,
Today, letโs talk about some of the Python questions you might face during a data analyst interview. Below, Iโve compiled the most commonly asked Python questions you should be prepared for in your interviews.
1. Why is Python used in data analysis?
Python is popular for data analysis due to its simplicity, readability, and vast ecosystem of libraries like Pandas, NumPy, Matplotlib, and Scikit-learn. It allows for quick prototyping, data manipulation, and visualization. Moreover, Python integrates seamlessly with other tools like SQL, Excel, and cloud platforms, making it highly versatile for both small-scale analysis and large-scale data engineering.
2. What are the essential libraries used for data analysis in Python?
Some key libraries youโll use frequently are:
- Pandas: For data manipulation and analysis. It provides data structures like DataFrames, which are perfect for handling tabular data.
- NumPy: For numerical operations. It supports arrays and matrices and includes mathematical functions.
- Matplotlib/Seaborn: For data visualization. Matplotlib allows for creating static, interactive, and animated visualizations, while Seaborn makes creating complex plots easier.
- Scikit-learn: For machine learning. It provides tools for data mining and analysis.
3. What is a Python dictionary, and how is it used in data analysis?
A dictionary in Python is an unordered collection of key-value pairs. Itโs extremely useful in data analysis for storing mappings (like labels to corresponding values) or for quick lookups.
Example:
4. Explain the difference between a list and a tuple in Python.
- List: Mutable, meaning you can modify (add, remove, or change) elements. Itโs written in square brackets
Example:
- Tuple: Immutable, meaning once defined, you cannot modify it. Itโs written in parentheses
Example:
5. How would you handle missing data in a dataset using Python?
Handling missing data is critical in data analysis, and Pythonโs Pandas library makes it easy. Here are some common methods:
- Drop missing data:
- Fill missing data with a specific value:
- Forward-fill or backfill missing values:
6. How do you merge/join two datasets in Python?
- pd.merge(): For SQL-style joins (inner, outer, left, right).
- pd.concat(): For concatenating along rows or columns.
7. What is the purpose of lambda functions in Python?
A lambda function is an anonymous, single-line function that can be used for quick, simple operations. They are useful when you need a short, throwaway function.
Example:
Lambdas are often used in data analysis for quick transformations or filtering operations within functions like
If youโre preparing for interviews, focus on writing clean, optimized code and understand how Python fits into the larger data ecosystem.
Here you can find essential Python Interview Resources๐
https://t.me/DataSimplifier
Like for more resources like this ๐ โฅ๏ธ
Share with credits: https://t.me/sqlspecialist
Hope it helps :)
Today, letโs talk about some of the Python questions you might face during a data analyst interview. Below, Iโve compiled the most commonly asked Python questions you should be prepared for in your interviews.
1. Why is Python used in data analysis?
Python is popular for data analysis due to its simplicity, readability, and vast ecosystem of libraries like Pandas, NumPy, Matplotlib, and Scikit-learn. It allows for quick prototyping, data manipulation, and visualization. Moreover, Python integrates seamlessly with other tools like SQL, Excel, and cloud platforms, making it highly versatile for both small-scale analysis and large-scale data engineering.
2. What are the essential libraries used for data analysis in Python?
Some key libraries youโll use frequently are:
- Pandas: For data manipulation and analysis. It provides data structures like DataFrames, which are perfect for handling tabular data.
- NumPy: For numerical operations. It supports arrays and matrices and includes mathematical functions.
- Matplotlib/Seaborn: For data visualization. Matplotlib allows for creating static, interactive, and animated visualizations, while Seaborn makes creating complex plots easier.
- Scikit-learn: For machine learning. It provides tools for data mining and analysis.
3. What is a Python dictionary, and how is it used in data analysis?
A dictionary in Python is an unordered collection of key-value pairs. Itโs extremely useful in data analysis for storing mappings (like labels to corresponding values) or for quick lookups.
Example:
sales = {"January": 12000, "February": 15000, "March": 17000}
print(sales["February"]) # Output: 15000
4. Explain the difference between a list and a tuple in Python.
- List: Mutable, meaning you can modify (add, remove, or change) elements. Itโs written in square brackets
[ ]
.Example:
my_list = [10, 20, 30]
my_list.append(40)
- Tuple: Immutable, meaning once defined, you cannot modify it. Itโs written in parentheses
( )
.Example:
my_tuple = (10, 20, 30)
5. How would you handle missing data in a dataset using Python?
Handling missing data is critical in data analysis, and Pythonโs Pandas library makes it easy. Here are some common methods:
- Drop missing data:
df.dropna()
- Fill missing data with a specific value:
df.fillna(0)
- Forward-fill or backfill missing values:
df.fillna(method='ffill') # Forward-fill
df.fillna(method='bfill') # Backfill
6. How do you merge/join two datasets in Python?
- pd.merge(): For SQL-style joins (inner, outer, left, right).
df_merged = pd.merge(df1, df2, on='common_column', how='inner')
- pd.concat(): For concatenating along rows or columns.
df_concat = pd.concat([df1, df2], axis=1)
7. What is the purpose of lambda functions in Python?
A lambda function is an anonymous, single-line function that can be used for quick, simple operations. They are useful when you need a short, throwaway function.
Example:
add = lambda x, y: x + y
print(add(10, 20)) # Output: 30
Lambdas are often used in data analysis for quick transformations or filtering operations within functions like
map()
or filter()
.If youโre preparing for interviews, focus on writing clean, optimized code and understand how Python fits into the larger data ecosystem.
Here you can find essential Python Interview Resources๐
https://t.me/DataSimplifier
Like for more resources like this ๐ โฅ๏ธ
Share with credits: https://t.me/sqlspecialist
Hope it helps :)
โค6