NumPy Dojo
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Welcome

Learn NumPy by doing

Short lessons with a live editor, then scenarios and quizzes to reinforce what you practiced. Follow the path below—or jump to any lesson topic or scenario when you need a refresher.

Start with Lesson 1Next up: Lesson 1 of 22

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Click a step to open it in the dojo.

  1. Lessons

    Go in order inside each topic. Complete the task in the editor, then use the Next button when you pass—concepts stack from Foundations through Linear Algebra.

  2. Scenarios

    Apply the same skills in short multi-step stories. They link back to lessons if you need a hint.

  3. Quizzes

    Check understanding and revisit weak spots via lesson links in explanations.

Lessons

Lesson progress0 / 220%

Scenarios

Scenario progress0 / 120%
013 steps

Data Analysis

Student Grade Analysis

<p>You&apos;re a teacher with exam scores for <strong>5 students</strong> across <strong>4 tests</strong>. You need to analyze performance, identify struggling students, and reason about the grade book as a single numerical object.</p><figure class="prose-figure"><img src="/illustrations/grades-matrix.png" width="1200" height="896" alt="5 by 4 grade grid: each row is a student, each column a test; shape 5 comma 4." loading="lazy" decoding="async" /><figcaption>Think of the sheet as one 2D array: each row is a student, each column a test—then row means and boolean masks have a clear meaning.</figcaption></figure><p>This scenario uses the same patterns as the <strong>Aggregation</strong> and <strong>Boolean indexing</strong> lessons.</p>

022 steps

Data Analysis

Weather Station Data

You're processing a week of temperature readings from 3 weather stations. Each station records a high and low temperature daily. You need to find trends and anomalies.

033 steps

Finance

Investment Portfolio Returns

You manage a portfolio of 4 stocks over 6 months. You need to calculate returns, find the best performer, and assess risk using standard deviation.

043 steps

Data Processing

Image Pixel Manipulation

You're working with a small 4×4 grayscale image represented as a NumPy array. You need to manipulate pixel values — normalize, threshold, and invert.

052 steps

Data Analysis

A/B Test Analysis

You ran an A/B test on your website. Group A (control) had 200 users, Group B (variant) had 200 users. You recorded conversion rates and need to analyze the results.

063 steps

Business

Inventory Management

You manage inventory for a small store with 6 products across 3 warehouse locations. You need to track stock levels, find shortages, and calculate reorder quantities.

072 steps

Data Processing

Survey Data Cleanup

You received survey responses (ratings 1-5) from 50 respondents across 8 questions. Some responses are invalid (0 or 6+). You need to clean, analyze, and summarize.

082 steps

Business

Retail Sales Forecasting

You have monthly sales data for a retail store over 12 months. You need to analyze trends, calculate moving averages, and identify the best/worst months.

092 steps

Math & Science

City Distance Calculator

You have coordinates for 4 cities and need to compute the distance matrix between all pairs. This is a common task in logistics, mapping, and machine learning (e.g., KNN).

102 steps

Everyday Math

Recipe Ingredient Scaler

You have a recipe that serves 4 people with specific ingredient amounts. You need to scale it for different party sizes using broadcasting — exactly how NumPy shines in everyday calculations.

112 steps

Everyday Math

Fitness Tracker Analytics

You're building a simple fitness tracker analysis. You have step counts for 4 weeks (28 days) and need to analyze daily, weekly, and overall performance.

122 steps

Math & Science

Engineering Equation Solver

You're an engineer solving a system of equations from a circuit analysis. Three loops in a circuit give you 3 equations with 3 unknowns (currents). This is exactly what np.linalg.solve is built for.