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MISSION 14 · PYTHON LISTS

Manifest of Many Parcels

Read an item by its zero-based slot, then build a total by visiting every item. Empty lists are real lists with no item to read.

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◇ Your mastery goalPython lists · Parcel manifests · Set A

Complete all 7 required tasks with a correct prediction, an inspected trace and an explanation that shows the concept. At least 4 must be independent checks, without answer-level help.

✓ Qualifying tasks: 0 / 7◎ Independent checks: 0 / 4 required
PRACTICE · 1 OF 7

Find one parcel

0 / 7 checks

Read the first parcel count from the manifest. Which value is stored at slot 0?

1
Read the starting collectionThese authored values are read-only inputs to your program.
slot 08slot 13slot 25slot 32

Requested slot: slot = 0

2
Predict before RunWhat value does that slot read?
3
Read from the listUse the requested slot.

Allowed: manifest[slot], total = 0, for item in manifest:, addition, and print(...).

List positions start at 0. An empty list has no first item; its sum stays at zero. This is a small bounded Python subset.

4
Collection state · inspected eventManifest items in order: slot 0 has 8; slot 1 has 3; slot 2 has 5; slot 3 has 2.

Manifest list

Starting values (read-only lesson input)

manifest = [8,3,5,2]

Positions start at index 0. Values are the parcel counts at those positions.

  1. Index 08
  2. Index 13
  3. Index 25
  4. Index 32

Border, ▶ marker and text identify the current read; color is an extra cue.

Help for this list puzzleHints build in steps. Worked help and solutions need a deliberate choice.

Highest help used on this case: none

For Further Reading and Exploration

These are outside sites with their own rules. You will see a notice before you leave. Pick one, not all.

  • Automate the Boring Stuff with Python

    Free book to read online. A chapter on lists covers indexes, slices and looping over a list.

    • Hands-on
    • May need an install
    • Ask an adult

  • CS50's Introduction to Programming with Python

    Free Harvard course with videos and notes. The loops lecture covers lists and looping over them.

    • Hands-on
    • Advanced
    • May count visits

  • MIT OpenCourseWare 6.100L

    Free college course notes and videos. It moves fast, so take one topic at a time. Look for the lectures on lists.

    • Hands-on
    • Advanced
    • May count visits

  • Raspberry Pi Foundation Projects

    Step-by-step Python projects. Pick one that keeps a list of things, then add an item. Some need hardware, so check the parts list.

    • Hands-on
    • May count visits