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ADM Python P.7

Production Loops with while

Repeating until a production target or condition is met.

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Your lesson guide

Objective

Write a while loop Update a counter safely Recognize and prevent infinite loops

Materials

For the online work: a browser and your engineering notebook. Follow the activity’s materials list for any physical build, and get teacher approval before using equipment.

Plan your time

Suggested work block: 45–60 minutes. Physical builds and projects may span several classes; follow your teacher’s schedule.

Learning Targets

  • Write a while loop
  • Update a counter safely
  • Recognize and prevent infinite loops

How to Use This Page

  1. Read the short lesson.
  2. Attempt every Practice Check before revealing the answer.
  3. Complete Predict It and Fix It by tracing and correcting code.
  4. Complete Modify It and Program It by writing Workcell-style Python code.
  5. Use the Mastery Check before moving to the next lesson.
Learn It

Python Idea + Workcell Connection

A while loop keeps repeating as long as its condition remains True. It is useful when the program should continue until a production target is reached.

The condition must eventually become False. If the variables in the condition never change, the loop can run forever.

A counter such as parts_completed += 1 is a common way to move the loop toward its stopping condition.

Worked Example

Trace This Code

Read every line and predict what the program would do before opening the practice check.

parts_completed = 0
production_goal = 5

while parts_completed < production_goal:
    print("Running cycle")
    parts_completed += 1

print("Production complete")
Practice Check A

Check Your Understanding

  1. What value starts in parts_completed?

    Check Answer

    0

  2. What line moves the loop toward stopping?

    Check Answer

    parts_completed += 1

  3. What danger exists if that line is removed?

    Check Answer

    The condition remains True and the loop can become infinite.

Rule: If you missed more than one question, reread Learn It and trace the example again before continuing.

1 · Predict It

Trace the Code

How many cycles run? What happens if parts_completed += 1 is removed?

Do first: Write your answer in your engineering notebook.

Reveal Self-Check

Five cycles run. Without the counter update, parts_completed stays 0 and the loop never reaches the goal.

2 · Fix It

Debug the Program

Find and correct every error before opening the answer.

parts_completed = 0

while parts_completed < 3:
    print("Cycle", parts_completed)
Reveal Debugging Check

Add parts_completed += 1 inside the loop so the condition eventually becomes False.

3 · Modify It

Change Working Code

Add the missing line needed to make the loop stop after three cycles.

Success Check

  • Your code is syntactically correct.
  • The change affects only the intended Workcell behavior.
  • You can explain what changed and why.

Evidence: Paste the revised code into your engineering notebook.

4 · Program It

Build It Yourself

Write a while loop that represents a Workcell processing parts until eight parts are complete.

Before You Finish

  • Trace the code once by hand.
  • Check variable names, colons, parentheses, and indentation.
  • Verify that the coordinates and logic match the written scenario.
  • Add useful comments.
Interactive Practice

Python Practice Lab

Edit the code, predict the output, then click Run Code. No physical Workcell is connected.

Browser Python

P.7 Practice

Ready
Output / Errors
Predict what the code will do, then click Run Code.

Tip: Press Ctrl+Enter (Cmd+Enter on Mac) to run. The mock arm object prints simulated Workcell actions instead of controlling hardware.

Practice Check B

Explain Your Code

Without looking back at Learn It, answer these in your notebook:

  1. What Python structure or idea did you use?
  2. What Workcell behavior would this code represent?
  3. What mistake would cause the code to behave incorrectly?
What a Strong Response Includes

A strong response names the Python idea accurately, connects it to a specific Workcell action or decision, and identifies a realistic syntax or logic error from this lesson.

Mastery Gate

Ready for the Next Lesson?

  • □ I can explain when to use a while loop.
  • □ I can update a counter safely.
  • □ I can identify a likely infinite loop.

Move on only when you can check every statement. If one is still uncertain, revisit the worked example or redo Fix It before continuing.

Command Reference

VEX Workcell Python API

Use the official VEX API only as a programming reference to verify method names and parameters. The examples use the configured arm name arm. No physical Workcell is required.

Open EXP Workcell Arm API
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Build your lesson report

Checkpoint: is your evidence ready?
  • Check calculations, units, labels, and measurements against the activity requirements.
  • Record what actually happened, including unexpected results.
  • Explain what you changed and why; attach required drawings, photos, CAD, or code in your classroom assignment.

Submit the evidence specified in the activity and your classroom assignment. The report below collects your notes, calculations, observations, and reflections; attach any required drawings, photos, CAD, or code separately.

A PDF download is not a submission. Review it, then upload it and any required attachments through your classroom assignment system.