Workshop 1

Follow along with the slides, then work through the lab below.

Two 20-minute labs on event bookings. Extensions are optional.

Lab 1: Values and conversion

Getting started (2 minutes)

• Open the lab notebook in Colab and save your own copy.
• Click the play button beside a code cell to run it. Work from top to bottom.
• Double-click text to edit an answer. Click outside when done.

Try the cell below.

1
greeting = "Ready to book!"
2
greeting

1. Predict, run, explain (3 minutes)

Predict each value and type: string (text), integer or float (decimal number). Then run the cells and record the results.

1
"6" + "0"

1
6 + 0

1
60 - 25

1
2.50 * 2

type(value) returns str for text, int for integers or float for decimal numbers. Use it to check your predictions.

Why do "6" + "0" and 6 + 0 differ?

1
type("6" + "0")

2. Plan an event (7 minutes)

There are 60 seats, 25 bookings and tickets cost £2.50.

1. Set capacity, booked and ticket_price in the first cell.
2. Calculate spaces and income in the next cell.
3. Run both. Expect 35 spaces and 62.5 in income (£62.50).

1
# Define capacity, booked and ticket_price here.

1
# Calculate spaces and income here.
2

3
print(spaces)
4
print(income)

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capacity = 60
2
booked = 25
3
ticket_price = 2.50

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spaces = capacity - booked
2
income = booked * ticket_price
3
print(spaces)
4
print(income)

Predict the results for 30 bookings. Set booked = 30 and run only that cell, then the cell below.

Why are the results unchanged? Rerun the calculation cell to update them.

Restore booked = 25 and rerun both cells before continuing.

1
print(spaces)
2
print(income)

3. Read a sign-up form (5 minutes)

The form gives "25" bookings. One more person books.

Convert booked_text with int, add one and store it as booked. Calculate and display spaces too. Expect 26 bookings and 34 spaces.

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capacity = 60
2
booked_text = "25"
3
# Update booked, calculate spaces, and display both.

1
capacity = 60
2
booked_text = "25"
3
booked = int(booked_text) + 1
4
spaces = capacity - booked
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print(booked)
6
print(spaces)

Predict booked_text + "1", then run it. Why is the result wrong for counting bookings?

1
booked_text + "1"

Lab 1 check (1 minute)

Explain why you need to:

• Rerun calculations after changing booked.
• Convert form text before adding one.

Extension A: A price from the form

Convert "2.50" with float. Calculate income for the 26 bookings from task 3. Expect 65.0 (£65.00).

Why would int fail here?

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price_text = "2.50"
2
# Use booked from task 3 to calculate income.

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price_text = "2.50"
2
income = booked * float(price_text)
3
income

Lab 2: Decisions and debugging

You can start here without finishing Lab 1.

4. Choose a message (6 minutes)

Use if, elif and else to set message. Assume bookings are non-negative integers.

Predict the messages in the table below. Write your code, then change booked to test each count.

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capacity = 60
2
booked = 25
3
# Choose message here.
4

5
print(message)

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capacity = 60
2
booked = 25
3
if booked > capacity:
4
    message = "Waiting list"
5
elif booked == capacity:
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    message = "Full"
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else:
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    message = "Spaces available"
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print(message)

Why is testing exactly 60 important?

5. Fix two bugs (5 minutes)

Run each cell and read the last line of its error. Fill in the table, then fix and rerun the code. Expect 34 spaces and 26 bookings.

1
capacity = 60
2
booked_text = "26"
3
capacity - booked_text

1
booking_count = 26
2
booking_cout

1
capacity = 60
2
booked_text = "26"
3
capacity - int(booked_text)

1
booking_count = 26
2
booking_count

6. Use the documentation (5 minutes)

Find the occupancy percentage for 25 bookings in a 60-seat room.

1. Calculate percentage = booked / capacity * 100.
2. Read the documentation for round. Round to one decimal place and store it as occupancy.
3. Display the result. Expect 41.7.

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capacity = 60
2
booked = 25
3
# Calculate percentage, then occupancy.

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capacity = 60
2
booked = 25
3
percentage = booked / capacity * 100
4
occupancy = round(percentage, 1)
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print(occupancy)
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print(round(percentage))

Compare round(percentage, 1) with round(percentage). What changes?

Optional: test 30 and 60 bookings. Expect 50.0 and 100.0 to one decimal place.

Lab 2 check (2 minutes)

Check your three messages, bug fixes and rounded percentage.

For a fresh check, restart the session from Colab’s Runtime menu. Use the play buttons to run your completed cells in order. If Lab 1 is unfinished, start at Lab 2.

Extension B: Can the whole group fit?

Set capacity = 60 and booked = 56. Use if and else to set group_message to Booking accepted if a group fits, or Not enough spaces otherwise.

Predict and test tickets_requested values of 3, 4 and 5. Keep booked unchanged.

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# Define capacity, booked and tickets_requested, then choose group_message.

Why should a request for exactly four tickets be accepted?

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capacity = 60
2
booked = 56
3
tickets_requested = 4
4
spaces = capacity - booked
5
if tickets_requested <= spaces:
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    group_message = "Booking accepted"
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else:
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    group_message = "Not enough spaces"
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print(group_message)

Extension C: A bug without an error message

Change > to >= in task 4. Which test catches the mistake? Try it, then restore >.