Data science/ML/AI

DSA Cheatsheet

Cheatsheet: Ensemble Learning in ML

AI/ML Cheatsheet

Softmax vs Sigmoid Functions

Two of the most common activation functions… and two of the most misunderstood.

Sigmoid: squashes input into a range between 0 and 1. Perfect for binary classification (yes/no problems). Example: spam or not spam.

Softmax: takes a vector of numbers and turns them into probabilities that sum to 1. Perfect for multi-class classification (cat vs dog vs horse).

👉 Rule of thumb:

Binary task → use Sigmoid.
Multi-class task → use Softmax.

Simple, but if you get this wrong, your model will never make sense.

Data Visualization Cheatsheet

Data Analyst 🆚 Data Engineer: Key Differences

Confused about the roles of a Data Analyst and Data Engineer? 🤔 Here's a breakdown:

👨‍💻 Data Analyst:

🎯 Role: Analyzes, interprets, & visualizes data to extract insights for business decisions.

👍 Best For: Those who enjoy finding patterns, trends, & actionable insights.

🔑 Responsibilities:
  🧹 Cleaning & organizing data.
  📊 Using tools like Excel, Power BI, Tableau & SQL.
  📝 Creating reports & dashboards.
  🤝 Collaborating with business teams.

Skills: Analytical skills, SQL, Excel, reporting tools, statistical analysis, business intelligence.

✅ Outcome: Guides decision-making in business, marketing, finance, etc.

⚙️ Data Engineer:

🏗️ Role: Designs, builds, & maintains data infrastructure.

👍 Best For: Those who enjoy technical data management & architecture for large-scale analysis.

🔑 Responsibilities:
  🗄️ Managing databases & data pipelines.
  🔄 Developing ETL processes.
  🔒 Ensuring data quality & security.
  ☁️ Working with big data technologies like Hadoop, Spark, AWS, Azure & Google Cloud.

Skills: Python, Java, Scala, database management, big data tools, data architecture, cloud technologies.

✅ Outcome: Creates infrastructure & pipelines for efficient data flow for analysis.

In short: Data Analysts extract insights, while Data Engineers build the systems for data storage, processing, & analysis. Data Analysts focus on business outcomes, while Data Engineers focus on the technical foundation.

Why is Kafka Called Kafka❔

Here’s a fun fact that surprises a lot of people.

The “Kafka” you use for real-time data pipelines is… named after the novelist Franz Kafka.

Why? Jay Kreps (the creator) once explained it simply:

- He liked the name.
- It sounded mysterious.
- And Kafka (the author) wrote a lot.

That last part is key.
Because Apache Kafka is all about writing: streams of events, logs, and data in motion.
So the name stuck.

Today, Millions of engineers across the globe talk about “Kafka” every single day… and most don’t realize they’re also invoking a 20th-century novelist.

It's funny how small choices like naming your project can shape how the world remembers it.

Cheatsheet: Bayes Theroem And Classifier

Important LLM Terms

🔹 Transformer Architecture
🔹 Attention Mechanism
🔹 Pre-training
🔹 Fine-tuning
🔹 Parameters
🔹 Self-Attention
🔹 Embeddings
🔹 Context Window
🔹 Masked Language Modeling (MLM)
🔹 Causal Language Modeling (CLM)
🔹 Multi-Head Attention
🔹 Tokenization
🔹 Zero-Shot Learning
🔹 Few-Shot Learning
🔹 Transfer Learning
🔹 Overfitting
🔹 Inference
🔹 Language Model Decoding
🔹 Hallucination
🔹 Latency

ML models don’t all think alike 🤖

❇️ Naive Bayes = probability
❇️ KNN = proximity
❇️ Discriminant Analysis = decision boundaries

Different paths, same goal: accurate classification.

Which one do you reach for first?