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Lists and loops: build your playlist

Use lists to store and change track titles. Learn to repeat input and append with a for loop, then build your own playlist.

List reminders

An index is an item’s position number. The first index is 0.

Code	Job
`tracks = ["Glow", "Orbit"]`	Create a list: square brackets, commas between items, quotes around text
`tracks[0]`	Access the first item using its index
`tracks[0] = "Spark"`	Access the first item and assign a new value
`tracks.append("Echo")`	Add a new item at the end
`tracks.remove("Orbit")`	Remove the first item with this value
`tracks.pop(1)`	Remove the second item, at index 1
`len(tracks)`	Count how many items are in the list

Task 1: Warm up your playlist

A. Fill three gaps. Access and print the first title. Remove index 1, then print the list’s length.

B. Run and check. Expect Glow, then 3.

Fill in the code3 marks

tracks = ["Glow", "Orbit", "Home"]
tracks.append("Echo")
print(tracks[Gap 1])
tracks.Gap 2(1)
print(Gap 3(tracks))

remove
1
len
append
0
pop

Repeat a set number of times

A loop repeats code. One repeat is an iteration.

for turn in range(3):
    print("Next track")
print("Playlist ready")

range(3) makes this loop repeat three times. Change the number to change the repeats.

Indentation means spaces before code. Use four spaces for lines inside the loop. Keep : after the for line.

The last print is outside the loop and runs once.

Task 2: Complete a for loop

A. Fill three gaps. Repeat Next track three times.

B. Run. Check that Playlist ready appears once, after the repeats.

Fill in the code3 marks

Gap 1 turn in Gap 2(Gap 3):
    print("Next track")
print("Playlist ready")

3
if
range
4
for
len

Task 3: Change the repeats

A. Edit: print Next track four times.

B. Move: print Playlist ready once, after the loop.

C. Run and check.

Loop reminder

Change the number in range(). Remove indentation from code after the loop.

Coding task2 marks

for turn in range(2):
    print("Next track")
    print("Playlist ready")

Add one reply each time

Create tracks = [] before the loop. Inside: take input → store the reply → append it.

In input("Track title? "), the text is the question. You type the reply when it runs.

Task 4: Collect three track titles

A. Add a for loop to collect three titles. Inside: take input into track, then append it to tracks.

B. Run and check with Glow, Orbit, Home, one at a time.

Input and append

track = input("Track title? ")
tracks.append(track)

Indent both lines. Use track without quotes.

Coding task3 marks

tracks = []
# Add a three-repeat loop: take input, then append.

print(tracks)

Task 5: Keep the earlier titles

What goes wrong if tracks = [] is moved inside the Task 4 loop, before input()? Write one short sentence.

Written answer1 mark

What would happen to the titles already added?

Students type their answer here.

Check before removing

if name in tracks: checks whether the title is in the list. Only remove it if it is there; removing a missing value causes an error.

Task 6: Polish the list

A. Fill three gaps. Access the first item and assign Spark. Remove Orbit if present. Print the list and its length.

B. Run. Expect ["Spark", "Home"], then 2.

Fill in the code3 marks

tracks = ["Glow", "Orbit", "Home"]
tracks[Gap 1] = "Spark"
name = "Orbit"
if name in tracks:
    tracks.Gap 2(name)
print(tracks)
print(Gap 3(tracks))

pop
len
1
remove
0
append

Task 7: Plan your own program

Write short notes.

A. Collect: where does the empty list go? How will you add three replies?

B. Afterwards: how will you replace the first title, safely remove a title, and print the list and its length?

Written answer2 marks

Write your plan for parts A and B.

Students type their answer here.

Task 8: Build your playlist

A. Collect.

Create tracks = [] before a for loop with range(3). Inside: take input into track, then append it.

B. Edit after the loop.

Take input into new_first; assign it to tracks[0].
Take input into remove_track; remove it only if it is in the list.

C. Show and test.

Print only the final list, then its length, on two lines. Try each test’s five replies one at a time, then check.

Test	Three titles	New first	Remove	Final count
1	Glow, Orbit, Home	Spark	Orbit	2
2	Rain, Cloud, Sun	Moon	Star	3

Stuck?

Use Tasks 4 and 6. Build and test one part at a time.

Coding task8 marks

# Create the empty list.

# Repeat input and append three times.

# After the loop: replace the first title using input.

# Take input for a title to remove; check before removing.

# Print the final list and its length.

Task 9: Save a loop reminder

Copy a three-repeat loop into your book. Label the for line, code inside, and code after the loop. Add: “Create the list before the loop.”

This book note has no platform marks.