Random Deep Dive — choice & shuffle

By the end of this lesson you can:

• Use random.choice(my_list) to pick one random item from any list.
• Use random.shuffle(my_list) to rearrange a list in place — and explain why you must not re-assign the result.
• Use random.sample(my_list, k) to pick k unique items in one move.

Two lessons ago we learned append, pop, remove, and sort. Last lesson we sliced lists with brackets. Today we shake them with the random module.

Quick refresher first. What did random.randint do?

import random

dice = random.randint(1, 6)
print("You rolled:", dice)

It gave us one whole number between 1 and 6 — both ends included. Today we ask: what if the "options" aren't numbers but anything we can put in a list? Predict the output:

import random

drinks = ["teh tarik", "kopi-O", "milo ais"]
pick = random.choice(drinks)
print("Today's drink:", pick)

Today's drink: kopi-O

Step 0 · import random

Every random tool lives inside the random module. One line at the top of your file unlocks them all.

import random

You only need it once per file, even if you call ten random functions later.

1 · random.choice(my_list) — pick one

The function returns one item from the list, chosen at random.

import random

snacks = ["kuih lapis", "keropok", "pisang goreng", "roti bakar"]
tonight = random.choice(snacks)
print("Tonight we eat:", tonight)

The list itself is not changed — choice just looks inside and returns one item. Call it again and you might get the same snack twice in a row. Perfect for Magic 8-Ball answers, daily quotes, or picking a random villager NPC line in a game.

2 · random.shuffle(my_list) — rearrange in place

This one changes the list. It scrambles the order — same items, new positions.

import random

players = ["Hafiz", "Aisyah", "Daniel", "Mei", "Priya"]
random.shuffle(players)
print(players)
# → ['Mei', 'Daniel', 'Priya', 'Hafiz', 'Aisyah']  (yours will differ)

Same trick as last lesson's sort: it works in place. Don't write players = random.shuffle(players) — shuffle returns None, so you'd wipe your list out.

3 · random.sample(my_list, k) — pick K unique

choice gives one. sample gives several — guaranteed all different.

import random

names = ["Hafiz", "Aisyah", "Daniel", "Mei", "Priya", "Lim", "Siti"]
winners = random.sample(names, 3)
print("Three lucky winners:", winners)
# → Three lucky winners: ['Siti', 'Hafiz', 'Mei']  (yours will differ)

Unlike shuffle, sample does not change the original list — it returns a brand-new list of k picks. And unlike calling random.choice three times, sample never picks the same item twice — perfect for raffles, secret-Santa drawings, or quiz-question sets.

Quick comparison

# choice    → one item, list unchanged, can repeat across calls
# shuffle   → reorders the list in place, returns None
# sample(k) → a new list of k different items, original unchanged

The job

Mei can never decide what to eat at the kantin. We'll build a tiny "roulette" that picks one drink, shuffles the menu order for variety, and finally draws three lucky winners for a free roti — all in one script.

Step 1 · The menu

import random

menu = ["nasi lemak", "mee goreng", "char kway teow", "roti canai", "laksa", "satay"]
drinks = ["teh tarik", "kopi-O", "milo ais", "sirap bandung"]
students = ["Hafiz", "Aisyah", "Daniel", "Mei", "Priya", "Lim", "Siti"]

Step 2 · Pick today's drink with choice

todays_drink = random.choice(drinks)
print("Today's drink of the day:", todays_drink)

Step 3 · Shuffle the menu for variety

random.shuffle(menu)
print("Today's menu order:")
for item in menu:
    print("-", item)

Notice the loop is just for item in menu — exactly the pattern from PY-L1-16. The shuffle has already changed menu in place, so we just walk it.

Step 4 · Draw three free-roti winners with sample

winners = random.sample(students, 3)
print("Free roti winners:")
for i, name in enumerate(winners, start=1):
    print(i, ".", name)

Step 5 · Assemble the whole script

Save as kantin_roulette.py:

Code

# kantin_roulette.py — Mei's kantin pick-of-the-day

import random

menu = ["nasi lemak", "mee goreng", "char kway teow", "roti canai", "laksa", "satay"]
drinks = ["teh tarik", "kopi-O", "milo ais", "sirap bandung"]
students = ["Hafiz", "Aisyah", "Daniel", "Mei", "Priya", "Lim", "Siti"]

todays_drink = random.choice(drinks)
print("Today's drink of the day:", todays_drink)

random.shuffle(menu)
print("Today's menu order:")
for item in menu:
    print("-", item)

winners = random.sample(students, 3)
print("Free roti winners:")
for i, name in enumerate(winners, start=1):
    print(i, ".", name)

Output (one possible run)

Today's drink of the day: milo ais
Today's menu order:
- laksa
- roti canai
- satay
- nasi lemak
- mee goreng
- char kway teow
Free roti winners:
1 . Priya
2 . Hafiz
3 . Siti

Run it three times — every run gives a different drink, a different menu order, and a different trio of winners. That's the randomness doing its job.

Three tasks. Run each at least twice — the outputs will differ.

import random

kuih = ["kuih lapis", "ondeh-ondeh", "seri muka", "kuih bahulu", "pisang goreng"]
today = random.choice(kuih)
print("Today's kuih:", today)

import random

names = ["Hafiz", "Aisyah", "Daniel", "Mei", "Priya", "Lim", "Siti"]
random.shuffle(names)
for name in names:
    print(name)

import random

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
winners = random.sample(numbers, 3)
for i, n in enumerate(winners, start=1):
    print(i, ".", n)

The random module has three list-friendly tools. random.choice picks one item and leaves the list alone. random.shuffle rearranges the list in place — never re-assign its result. random.sample hands back a new list of k unique items. Together they power Magic 8-Balls, song shufflers, lucky draws, and most surprise-of-the-day apps.