Constrictor

Get ready for the CodeSignal General Coding Assessment in Python

Learn the Python, practice solving problems as a solution() function against hidden tests, and watch your code run one step at a time. Then sit timed four-question mocks.

Start the first lessonTry free Mock 1

Free: chapters 1 to 4, the first lesson of Solve it as a function, and Mock 1. No account needed.

Not affiliated with or endorsed by CodeSignal.

ticket_counter.pyStatic worked example
  1. tickets = int(input("Tickets? "))
  2. price = 4
  3. total = tickets * price
  4. print("Total:", total)
Input"3"text
After int()3integer
price4integer
total12integer
OutputTotal: 12

Why int()? input() returns text. Convert it before doing arithmetic. Change the code yourself in the lessons.

Five steps, in order.

Each step builds on the one before. Start at step 1 if Python is new to you, or jump to the step you need. Practice comes first: every lesson is short reading and then code you write and run.

  1. Foundations

    Variables, numbers, strings, logic, loops, collections and functions, in small programs you run in the browser.

  2. Solve it as a function

    Write solution(...), run sample tests, then submit against hidden tests. Read a problem, handle edge cases, and test speed by experiment.

  3. Six patterns

    Arrays and strings, hash maps and sets, 2D grids, sorting with two pointers and windows, prefix sums, and simulation.

  4. Eight timed mocks

    Four function questions in 70 minutes, hidden tests, any order. The questions are our own. Mock 1 is free.

  5. Readiness

    See which problems you fully solved, your solve times, and your mock results by question type, then practice what is next.

See your code run.
Find the wrong step.

When a test fails, the number alone rarely tells you why. In the lessons, step through a run to follow names and values through assignments, branches, loops, and function calls, and find the instruction where the result stops matching your prediction.

The ticket example shows the idea: int() turns "3" into the number 3 before multiplication. Leave out that conversion and Python repeats the text instead.

Find the next thing
you want to understand.

18 chapters. 98 lessons. The links below come directly from the current course, not a separate marketing syllabus.

Search titles and lesson explanations.

Foundations

Member practice, some free

Numbers & Math

Member practice, some free

Strings

Member practice, some free

Logic & Decisions

Member practice, some free

Loops

Member practice

Collections

Member practice

Functions

Member practice

Solve it as a function

Member practice, some free

Arrays & strings

Member practice

Hash maps & sets

Member practice

2D grids

Member practice

Sorting, two pointers & windows

Member practice

Prefix sums & speed

Member practice

Simulation & parsing

Member practice

Test strategy

Member practice

Errors, Modules & Files

Member practice

Objects & Classes

Member practice

Data at Work

Member practice

Build a practice habit,
not a watch list.

If you are starting from scratch, take the chapters in order. Foundations introduce printing, comments, variables, and types. Later tasks reuse those ideas rather than asking you to forget everything at the end of a page.

If you already know some Python, use the curriculum to choose a weak spot. Search for a specific concept, read its explanation, and attempt the exercises before looking at a solution. Being able to explain an example is a useful start; being able to change it is a stronger check.

A practical way to use a lesson

  • Predict the output before you press Run.
  • Change one thing at a time when debugging.
  • Use a hint when you need a nudge, not a finished answer.
  • After solving a task, explain why your code works.
  • Come back later and solve it without copying your first attempt.

Projects bring several concepts together. They are practice tasks, not a promise of a job, a certificate, or a particular learning speed.

A few things worth knowing.

What is the CodeSignal General Coding Assessment?

According to CodeSignal's help center, it has four questions and 70 minutes, though the employer can change the time. You see all four at once, work in any order, and Python 3 is available. Constrictor is a separate course and is not affiliated with or endorsed by CodeSignal. Read your own invitation for the rules that apply to you. The mocks here follow that shape: four function questions, 70 minutes, hidden tests. All problems are our own.

Can I start if I have never coded before?

Yes. Begin with the first lesson and work forward. The early chapters introduce the basic vocabulary through small programs. You do not need to install Python to try the browser exercises. A keyboard and a modern desktop browser are the most comfortable setup for editing code.

What is free, and what needs a subscription?

Free, with no account needed: the first four chapters (Foundations, Numbers & Math, Strings, and Logic & Decisions), the first lesson of Solve it as a function, and Mock 1. Everything else is member practice: the other chapters, including the six pattern chapters, and Mocks 2 to 8. Lesson explanations are public throughout the curriculum. Later practice requires a signed-in account with active course access, when account services are available. Any available subscription amount and billing interval are shown in the secure checkout before you pay; there is no advertised price here.

Does this run real Python?

Yes. The lesson workspace uses Pyodide to run Python in your browser, not a collection of simulated outputs. The worked ticket example on this page is an illustration, not a live interpreter. Opening a practice lesson loads the runtime, which may take a moment on a slow connection.

What happens when my code is wrong?

The workspace shows execution errors and checks your attempt against the task. Hints and lesson-specific feedback help you investigate common mistakes. You can inspect the output and step through the recorded execution. Using help does not prevent later mastery: return and solve the task unaided to demonstrate it, without earning duplicate completion rewards. A passing check applies to that exercise; it does not prove a program is correct for every possible input.

Will my progress follow me to another device?

Guest practice saves progress in this browser. Signing in enables account progress sync when the connected service is configured and available. Clearing browser storage can remove guest progress. Account access and synchronization depend on a connection; do not treat the browser editor as your only backup for important code.

Can I use this for data analysis practice?

Use the live curriculum to see which data lessons are currently included. Lessons can load Python packages such as pandas and matplotlib when their tasks need them. Browser Python has different file and network constraints from a local Python installation, so it is a practice environment rather than a replacement for your production tools.

Do I need reminders or notifications?

No. Practice does not require email or push reminders. Account reminder settings are optional, and browser push also requires your permission. Keep them off if a quieter workflow makes it easier to return on your own terms.

Write the first function.
Then sit a mock.

Start the first lessonTry free Mock 1

Try the free part first. Decide what comes next after you have tried the work.