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Python & DataFree

Turn messy tables into trustworthy analysis.

Pandas Fundamentals

Learn DataFrames, selection, filtering, groupby, merge, reshape, time series, and performance with real pandas running in your browser.

What you will leave with

You can take raw tabular data through a clear, reproducible pandas workflow and explain every transformation along the way.

Modules
7
Duration
~8 hours
Level
Beginner to Intermediate
Access
Free course
  • Interactive pandas animations
  • In-browser Pyodide playground
  • Acme SaaS running dataset

What you will be able to do

What this course prepares you to do.

The curriculum is organized around these 4 practical outcomes.

Build and inspect DataFrames confidently

Select, filter, and clean rows without silent mistakes

Aggregate and combine related tables

Reshape and analyze time-based data efficiently

Curriculum

Every module earns the next one.

Open a module to inspect every section before you start. Your progress follows you through the course.

01
Module 1

DataFrames & Series: The Building Blocks

BeginnerFree

Why Pandas for Data Science, The Acme SaaS Running Dataset, DataFrame Anatomy, Rows, Columns, Index, and more.

View 5 sections
  1. 1Why Pandas & The Acme SaaS Dataset
  2. 2DataFrame Anatomy: Rows, Columns, Index
  3. 3Series: The Underlying Building Block
  4. 4Inspecting Data: head, info, describe
  5. 5Mutability vs. Copies: Avoiding the Common Trap
75 min5 sections
Open module
02
Module 2

Selecting & Filtering: loc, iloc, query

BeginnerFree

Column selection, [], dot access, and the gotchas, loc, Label-based access, iloc, Position-based access, and more.

View 5 sections
  1. 1Column Selection: The Three Ways
  2. 2loc: Label-Based Selection
  3. 3iloc: Position-Based Selection
  4. 4Boolean Masks: Filtering by Condition
  5. 5query(): Readable Filter Syntax
75 min5 sections
Open module
03
Module 3

Aggregation & GroupBy: Split-Apply-Combine

IntermediateFree

The split-apply-combine mental model, groupby() with single and multiple keys, agg(), multiple aggregations at once, and more.

View 5 sections
  1. 1The Split-Apply-Combine Mental Model
  2. 2groupby(): Single and Multi-Key Grouping
  3. 3agg(): Multiple Aggregations at Once
  4. 4transform vs aggregate vs apply
  5. 5Named Aggregations & Result Hygiene
75 min5 sections
Open module
04
Module 4

Joining DataFrames: merge with validate

IntermediateFree

merge(), inner, left, right, outer, on, left_on, right_on, controlling the keys, validate='one_to_many', catching cardinality bugs early, and more.

View 5 sections
  1. 1merge(): The Four How Modes
  2. 2Controlling Keys: on, left_on, right_on
  3. 3Cardinality: validate Saves Lives
  4. 4concat(): Stacking and Aligning
  5. 5join(): Merging by Index
70 min5 sections
Open module
05
Module 5

Reshaping Data: Wide ⇄ Long

IntermediateFree

Wide format vs long format, same data, two shapes, melt(), flatten wide to long, pivot() and pivot_table(), widen long to wide, and more.

View 5 sections
  1. 1Wide vs Long: Two Shapes, Same Data
  2. 2melt(): Flattening Wide to Long
  3. 3pivot() and pivot_table(): Widening to Wide
  4. 4stack() and unstack(): MultiIndex Toggles
  5. 5Choosing the Right Shape for the Job
65 min5 sections
Open module
06
Module 6

Time Series Essentials

IntermediateFree

Parsing dates, pd.to_datetime() and pitfalls, DatetimeIndex, the unlock for resample and rolling, resample(), period bucketization, and more.

View 5 sections
  1. 1Parsing Dates: to_datetime() and Pitfalls
  2. 2DatetimeIndex: The Time-Aware Index
  3. 3resample(): Bucketizing by Period
  4. 4rolling(): Windows Over Time
  5. 5Timezones: Naive vs Aware
65 min5 sections
Open module
07
Module 7

Common Pitfalls & Performance

IntermediateFree

SettingWithCopyWarning, what it really means, Vectorize, don't loop, the 100× speedup, dtypes, when pandas guesses wrong, and more.

View 5 sections
  1. 1SettingWithCopyWarning: Understanding & Fixing
  2. 2Vectorization: Why apply() Is Often Wrong
  3. 3dtypes: When Pandas Guesses Wrong
  4. 4Missing Data: NaN, None, and Promotions
  5. 5Profiling: Finding the Slow Line
65 min5 sections
Open module

Who this course is for

Built for people who need to use the skill.

Start with the background you have. The prerequisite notes above tell you exactly what is assumed.

01

Python learners moving into data work

02

Spreadsheet users adopting reproducible analysis

03

Analysts preparing for pandas interviews

Start the course

Begin with DataFrames & Series: The Building Blocks.

Module 1 introduces the language and example used throughout the rest of the course.

Open Module 1
Pandas Fundamentals for Data Science | Let's Data Science | Let's Data Science