✅ Data Science Fundamental Concepts You Should Know 📊🧠

1️⃣ Data Collection
Gathering raw data from various sources like databases, APIs, or web scraping for analysis.

2️⃣ Data Cleaning & Preprocessing
Preparing data by handling missing values, removing duplicates, correcting errors, and formatting for analysis.

3️⃣ Exploratory Data Analysis (EDA)
Using statistics and visualization to understand data patterns, trends, and detect outliers.

4️⃣ Statistical Inference
Drawing conclusions about populations using sample data through hypothesis testing, confidence intervals, and p-values.

5️⃣ Data Visualization
Creating charts and graphs (bar, line, scatter, histograms) to communicate insights clearly using tools like Matplotlib, Seaborn, or Tableau.

6️⃣ Feature Engineering
Transforming raw data into meaningful features that improve model performance, such as scaling, encoding and creating new variables.

7️⃣ Machine Learning Basics
Building predictive models by training algorithms on data:
⦁ Supervised Learning (regression, classification)
⦁ Unsupervised Learning (clustering, dimensionality reduction)

8️⃣ Model Evaluation
Assessing model accuracy using metrics like accuracy, precision, recall, F1 score (classification) and RMSE, MAE (regression).

9️⃣ Model Deployment
Putting your trained model into production so it can make real-time predictions or support decision-making.

🔟 Big Data & Tools
Handling large datasets using technologies like Hadoop, Spark, and databases such as SQL/NoSQL.

1️⃣1️⃣ Programming & Libraries
Essential coding skills in Python or R, with libraries like Pandas, NumPy, Scikit-learn for analysis and modeling.

1️⃣2️⃣ Data Ethics & Privacy
Ensuring responsible use of data, respecting privacy laws (GDPR), and avoiding biases in models.

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Famous programming languages and their frameworks


1. Python:

Frameworks:
Django
Flask
Pyramid
Tornado

2. JavaScript:

Frameworks (Front-End):
React
Angular
Vue.js
Ember.js
Frameworks (Back-End):
Node.js (Runtime)
Express.js
Nest.js
Meteor

3. Java:

Frameworks:
Spring Framework
Hibernate
Apache Struts
Play Framework

4. Ruby:

Frameworks:
Ruby on Rails (Rails)
Sinatra
Hanami

5. PHP:

Frameworks:
Laravel
Symfony
CodeIgniter
Yii
Zend Framework

6. C#:

Frameworks:
.NET Framework
ASP.NET
ASP.NET Core

7. Go (Golang):

Frameworks:
Gin
Echo
Revel

8. Rust:

Frameworks:
Rocket
Actix
Warp

9. Swift:

Frameworks (iOS/macOS):
SwiftUI
UIKit
Cocoa Touch

10. Kotlin:
- Frameworks (Android):
- Android Jetpack
- Ktor

11. TypeScript:
- Frameworks (Front-End):
- Angular
- Vue.js (with TypeScript)
- React (with TypeScript)

12. Scala:
- Frameworks:
- Play Framework
- Akka

13. Perl:
- Frameworks:
- Dancer
- Catalyst

14. Lua:
- Frameworks:
- OpenResty (for web development)

15. Dart:
- Frameworks:
- Flutter (for mobile app development)

16. R:
- Frameworks (for data science and statistics):
- Shiny
- ggplot2

17. Julia:
- Frameworks (for scientific computing):
- Pluto.jl
- Genie.jl

18. MATLAB:
- Frameworks (for scientific and engineering applications):
- Simulink

19. COBOL:
- Frameworks:
- COBOL-IT

20. Erlang:
- Frameworks:
- Phoenix (for web applications)

21. Groovy:
- Frameworks:
- Grails (for web applications)

✅10 Most Useful SQL Interview Queries (with Examples) 💼

1️⃣ Find the second highest salary:

SELECT MAX(salary)  
FROM employees  
WHERE salary < (SELECT MAX(salary) FROM employees);

2️⃣ Count employees in each department:

SELECT department, COUNT(*)  
FROM employees  
GROUP BY department;

3️⃣ Fetch duplicate emails:

SELECT email, COUNT(*)  
FROM users  
GROUP BY email  
HAVING COUNT(*) > 1;

4️⃣ Join orders with customer names:

SELECT c.name, o.order_date  
FROM customers c  
JOIN orders o ON c.id = o.customer_id;

5️⃣ Get top 3 highest salaries:

SELECT DISTINCT salary  
FROM employees  
ORDER BY salary DESC  
LIMIT 3;

6️⃣ Retrieve latest 5 logins:

SELECT * FROM logins  
ORDER BY login_time DESC  
LIMIT 5;

7️⃣ Employees with no manager:

SELECT name  
FROM employees  
WHERE manager_id IS NULL;

8️⃣ Search names starting with ‘S’:

SELECT * FROM employees  
WHERE name LIKE 'S%';

9️⃣ Total sales per month:

SELECT MONTH(order_date) AS month, SUM(amount)  
FROM sales  
GROUP BY MONTH(order_date);

🔟 Delete inactive users:

DELETE FROM users  
WHERE last_active < '2023-01-01';

✅ Tip: Master subqueries, joins, groupings & filters – they show up in nearly every interview!

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Ever wondered what the difference is between a Data Analyst and a Data Scientist? Both roles are in high demand, but they tackle data in different ways.

How to enter into Data Science

👉Start with the basics: Learn programming languages like Python and R to master data analysis and machine learning techniques. Familiarize yourself with tools such as TensorFlow, sci-kit-learn, and Tableau to build a strong foundation.

👉Choose your target field: From healthcare to finance, marketing, and more, data scientists play a pivotal role in extracting valuable insights from data. You should choose which field you want to become a data scientist in and start learning more about it.

👉Build a portfolio: Start building small projects and add them to your portfolio. This will help you build credibility and showcase your skills.

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10 Books on Data Science & Data Analysis will be posted on this channel daily basis

Book 1. Python for Data Analysis

Publisher: O'Reilly

wesmckinney.com/book/

Give it a like if you want me to continue ❤️

2. Fundamentals of Data Visualization

Publisher: O'Reilly

clauswilke.com/dataviz/

Like for more ❤️

3. Hands-On Data Visualization

Publisher: O'Reilly

handsondataviz.org

10 Data Science Books

4. R for Data Science

Publisher: O'Reilly

🖇️ r4ds.hadley.nz

10 Data Science Books

5. Data Science at the Command Line

Publisher: O'Reilly

jeroenjanssens.com/dsatcl/

10 Data Science Books

6. Introduction to Probability for Data Science

Publisher: Michigan University

probability4datascience.com

7. Think Stats

Publisher: O'Reilly

https://greenteapress.com/thinkstats2/thinkstats2.pdf

8. Mining Social Media

Publisher: No Starch Press

🖇️ socialdata.site

9. Kafka, The Definitive Guide

Publisher: O'Reilly

https://assets.confluent.io/m/2849a76e39cda2bd/original/20201119-EB-Kafka_The_Definitive_Guide-Preview-Chapters_1_thru_6.pdf

10 Data Science Books