Is the Lists & Looping lesson free?

The interactive Lists & Looping lesson is part of Pro (₹299/month). The first 5 lessons of the track are free — no account or card needed.

How long does the Lists & Looping lesson take?

About 6 minutes end-to-end. It's a hands-on lesson — you read a paragraph, edit the code, and run it in the same tab.

Do I need to install Python to try the Lists & Looping lesson?

No install required. PyRun runs real CPython in your browser via Pyodide (Python compiled to WebAssembly). Works on Chrome, Firefox, Safari, and Edge — desktop or mobile.

What level is the Lists & Looping lesson?

Beginner level. No prior Python required — good starting point.

Lists & Looping

Beginner
6 min
Fundamentals
basics · lists
Try it

Lesson 7 of 43

In this track

You’ll be able to

Create, index, and modify lists in place
Iterate over lists with for and enumerate()
Add and remove items with append(), pop(), remove()
Sort lists in place and get sorted copies with sorted()

Why this matters

Lists are the default container in every Python codebase, and for loops drive everything from ETL pipelines to ML training epochs. Understanding iteration is the difference between shipping code and copy-pasting Stack Overflow.

Common pitfalls

Mutating a list while iterating: for x in lst: lst.remove(x) skips elements. Iterate over lst[:] or build a new list.
Using list = [1,2,3] as a variable name. It shadows the built-in and breaks list(range(5)) later.
Assuming a = b copies the list. It aliases; use a = b.copy() or a = b[:] to duplicate.

Beginner · 5 minWhile Loops & break/continueLoop until a condition fails. Bail out or skip with break/continue.Beginner · 5 minSlicingCarve up lists and strings with [start:stop:step].Beginner · 7 minIf / Else & LoopsMake decisions and repeat yourself — but only on purpose.

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You’ll be able to

Create, index, and modify lists in place
Iterate over lists with for and enumerate()
Add and remove items with append(), pop(), remove()
Sort lists in place and get sorted copies with sorted()

Why this matters

Common pitfalls

Mutating a list while iterating: for x in lst: lst.remove(x) skips elements. Iterate over lst[:] or build a new list.
Using list = [1,2,3] as a variable name. It shadows the built-in and breaks list(range(5)) later.
Assuming a = b copies the list. It aliases; use a = b.copy() or a = b[:] to duplicate.

You’ll be able to

Why this matters

Common pitfalls

Related lessons

You’ll be able to

Why this matters

Common pitfalls

Related lessons