Variables feel invisible
You write x = 5 but have no idea what's actually happening in memory.
Values change silently in memory. If you can't see the current state, debugging becomes pure guesswork.
Variables lesson live
200 coding drills
Runs in browser
No install
See Python run, step by step
本物のPythonを書いてブラウザで実行し、各行が変数と出力をどう変えるかを見られます。
ブラウザで本物のPythonを書く。行の意味がわからなくなったら、ビジュアライザーで変数・出力・実行の変化を一行ずつ見られます。
変数レッスン公開中
200のコーディングドリル
ブラウザで実行
インストール不要
Variables Learning / Lesson 1 of 9
What is a variable?
Code Trigger
name = "StepTrace"
Before Python runs the line, memory is empty.
Memory / RAM
Before Python runs the line
Value
"StepTrace"
RAM Address
"StepTrace"
name
"StepTrace"
Step 1 of 4
← Previous
▶ Play
Next →
Python is hard when you can't see what the code is doing.
Loops move too fast
Your for loop runs instantly. You never see each iteration.
A loop runs 100 times in a millisecond. Beginners need to slow down and watch the mechanics iteration by iteration.
Output appears, but the why is unclear
Output appears, but why?
The terminal shows the result, but not how each line changed the state.
Seeing the final answer isn't enough. You need to connect the print statement to the logic that generated it.
Learn it. Run it. Trace it.
The StepTrace workflow is designed for understanding, not just typing.
Learn Variables visually
See how memory works with interactive RAM diagrams and guided lessons.
Watch a concept execute
Start with Variables and see how names, values, and memory change.
Practice with 200 drills
Write real Python, run it instantly, and get immediate feedback.
Write real Python
Practice with auto-graded coding drills in the browser.
Trace execution when stuck
Open the visualizer to see your code run line by line, watching variables change.
Scrub through each step
When stuck, open the visualizer and inspect each line, variable, and output.
Learn
Start with Variables, taught visually.
See how memory works with interactive RAM diagrams and guided lessons.
Lesson 1 of 9
What is a variable?
Code Trigger
name = "Andy"
Step 3 of 4
Memory / RAM
Value
"Andy"
Variable:name
Python reserves a spot in memory, labels it with the variable name, and stores the value there.
Live Module
Start with Variables, taught visually.
Before you can write complex logic, you need to understand memory. Our guided Variables module teaches you how Python stores data using interactive RAM cards, real code execution, and clear beginner explanations.
- Understand assignment, reassignment, and naming.
- See the difference between variable names and their values.
- Test your mastery before moving to independent practice.
Lesson 1 of 9
What is a variable?
Code Trigger
name = "Andy"
Memory / RAM
Before Python runs the line
Value
"Andy"
In RAM"Andy"
name"Andy"
Python has not created anything yet.
Practice
200 drills to build Python muscle.
Write real Python, run it instantly, and get immediate feedback.
Exercise 2/5 Check your knowledge
10 XP
Create a variable named score and assign it the value 100.
# write your code below:
score = 100
▶ Run
✓ Check Answer
✓ Test passed! Test passed: score is 100
200 Drills
200 coding drills to build real Python muscle.
Write code, run it, get feedback, and trace the execution when the result does not make sense. Real practice beats passive video watching every time.
01. Variable Swapping
Swap the values of a and b without using hardcoded numbers.
02. Greeting Message
Combine strings to create a welcome message.
02. Greeting Message
Trace
▶ Run Code
Create a variable called greeting and set it to "Welcome, " + name.
# Write your code below
name = "Learner"
greeting = "Welcome, " + name
print(greeting)
✓ Tests Passed! The variable greeting exists and holds the correct value.
Visualizer
Stop guessing what each line does.
The visualizer is your execution microscope.
Step-by-step traceStep 2 of 6
1 for i in range(3):
2 print(i)
3
Variables
i0
Output
0
← Previous
▶ Play
Next →
Step-by-step trace
1 for i in range(3):
2 print(i)
3
Variables
i
Output
← Previous
▶ Play
Next →
Visualizer
Scrub through every step of your logic.
When you trace your code, you control time. When stuck, open the visualizer and inspect each line, variable, and output backwards and forwards.
Like a DVR for your Python code.
Missions
Turn variables into a mission.
Variable Snake makes learning feel like playing.
Missions
Turn variables into a mission.
Unlock Variable Snake after the Variables lesson — a short reward mission, not the main product.
Stop guessing what your Python code does.
Start with Variables, practice with real drills, and trace the code when it stops making sense.