PY-L1-07 · Listening to the User · input()

Learning Goals

3 min

By the end of this lesson you can:

Ask the user a question with input() and store their answer.
Remember that input() always gives back a string.
Convert text answers into numbers using int() and float().

Warm-Up

5 min

In our Mad Libs game last lesson, every silly word lived at the top of the file. To play with a friend, you had to edit the file. That isn't really a game — yet.

Quick thought puzzle: how would your Mad Libs change if your friend could just type their words straight into the program when they wanted to play?

Tip

Today's tool — input() — turns your scripts into proper conversations. The same skill powers chatbots, calculators, and adventure games.

New Concept · Two-Way Conversations

12 min

Part 1 · The input() function

input() pauses your program and waits for the user to type something and press Enter. Whatever they type lands in a variable as a string.

name = input("What is your name? ")
print("Hello,", name)

The text inside input("...") is the prompt — the question shown to the user.

Style tip

Always end your prompt with a space, so the answer doesn't smush against the question. "Name? " is friendlier than "Name?".

Part 2 · input() always gives back a string

Even if the user types only digits, Python stores them as a string:

age = input("How old are you? ")
print(age + 1)

Python complains because "12" is a string. We can't add a string and a number with +.

Part 3 · Convert with int() and float()

Two tiny helpers turn numeric strings into real numbers:

int("12") → 12 — for whole numbers
float("3.14") → 3.14 — for decimals

The classic two-step pattern:

age_text = input("How old are you? ")
age      = int(age_text)
print("Next year you'll be", age + 1)

Or, the same thing in one tidy line — call int() right around input():

age = int(input("How old are you? "))
print("Next year you'll be", age + 1)

Part 4 · Where to type your answer

Different editors hand input() answers in slightly different places:

VS Code: click the green ▶ Run Python File button (top-right). Your prompt appears in the Terminal panel at the bottom — type there and press Enter.
online-python.com: click the Input tab on the right, type each answer on its own line first, then click Run.

Watch out

If the user types something that isn't a valid number, int(...) crashes. We will learn a safe way to handle this in Level 2 — for now, trust the user to type correctly.

Worked Example · A Personalised Greeter

12 min

We will build a tiny program that asks two questions and answers back. Save this as greeter.py.

Code

# greeter.py — ask the user some questions, then reply

# 1. Ask for a name (a string is fine — no conversion needed)
name = input("What is your name? ")

# 2. Ask for age, then convert to int
age_text = input("How old are you? ")
age      = int(age_text)

# 3. Build a friendly response
print()
print("Selamat datang,", name + "!")
print("Next year you'll be", age + 1, "— exciting!")

# 4. A little maths on the answer
months_alive = age * 12
print("You have been alive for roughly", months_alive, "months.")

When you run it, the terminal looks like this (lines you type are bold):

Output

What is your name? <strong>Aisyah</strong>
How old are you? <strong>12</strong>

Selamat datang, Aisyah!
Next year you'll be 13 — exciting!
You have been alive for roughly 144 months.

The compact version

Once you're comfortable, you can fold the conversion into one line:

age = int(input("How old are you? "))
print("In ten years you'll be", age + 10)

Both versions do the same thing. The two-step version is easier to read; the compact version is shorter. Pick whichever helps you understand the code.

Asking for a decimal

height = float(input("Your height in metres? "))
print("Half your height is", height / 2, "metres.")

Try It Yourself

13 min

Type each task into your editor. Run it. Fix any typos before moving on.

01 Echo bot

Ask the user "What did you say?" and store their answer in a variable. Then print "You said: " followed by the answer.

Hint

Two lines of code: one input(...), one print(...). No conversion needed because we're just echoing text.

02 Doubler

Ask the user for a number. Convert it with int(). Print the number, then print double the number.

Hint

n = int(input("A number? ")), then print(n * 2).

03 Talkative Mad Libs

Re-do this short Mad Libs sentence — but ask the user for the missing words instead of hard-coding them:

"Today, " + name + " ate " + str(count) + " pieces of " + food + " in " + place + "."

Use input() for name, food, and place. Use int(input(...)) for count.

Hint

Four input() calls — three plain, one wrapped in int(...). Then build the sentence with + and str() as in PY-L1-06.

Mini-Challenge · Mamak Order Calculator

8 min

Build a tiny mamak order calculator that talks to the user.

Your file must include:

An input() for the customer's name (no conversion).
An input() for how many roti_canai they want — convert with int(). Each roti canai costs RM 2.00.
An input() for how many teh_tarik they want — convert with int(). Each teh tarik costs RM 2.50.
Calculate the total in a variable.
Print a friendly receipt: greeting by name, item lines, and the total in RM.

Stretch goal. Also ask "How many friends are sharing the bill?" and print how much each person pays (total / friends).

Show one possible solution

# mamak_order.py — a friendly mamak calculator

# 1. Ask the customer
name       = input("What's your name? ")
roti_qty   = int(input("How many roti canai? "))
teh_qty    = int(input("How many teh tarik? "))

# 2. Prices and total
roti_price = 2.00
teh_price  = 2.50
total      = roti_qty * roti_price + teh_qty * teh_price

# 3. Receipt
print()
print("=" * 32)
print("   Mamak Code — Order Receipt")
print("=" * 32)
print("Customer:    ", name)
print("Roti canai:  ", roti_qty, "x RM", roti_price)
print("Teh tarik:   ", teh_qty, "x RM", teh_price)
print("-" * 32)
print("TOTAL:        RM", total)
print("=" * 32)

# Stretch — split between friends
friends   = int(input("How many friends are sharing? "))
each_pays = total / friends
print("Each person pays: RM", each_pays)

Recap

3 min

Our programs are no longer one-way. With input() we can ask, and with int() and float() we can do real maths on the answers.

Vocabulary Card

input(): Pauses the program and reads a line of text from the user.
prompt: The little question shown by input(). End it with a space.
int(): Turns a numeric string like "12" into the int 12.
float(): Turns a decimal string like "3.14" into the float 3.14.

Homework

4 min

Create a new file called calc.py — a tiny personal calculator.

Rules:

Ask the user three questions: their name, their current_age, and a target_age (like 100).
Convert both ages with int().
Calculate years_to_go = target_age - current_age.
Print a friendly multi-line reply that names the user and shows the result.
Stretch — also calculate years_in_school = current_age - 5 (assuming Standard 1 starts at age 7, kindergarten at 5) and print it.

Bring it to the next lesson — we'll run each other's calculators!

Sample · calc.py

# calc.py — a tiny personal calculator

# 1. Questions for the user
name        = input("What is your name? ")
current_age = int(input("How old are you now? "))
target_age  = int(input("Pick a target age (e.g., 100): "))

# 2. Maths
years_to_go = target_age - current_age

# 3. Reply
print()
print("Hi", name + "!")
print("You have", years_to_go, "years to go until you turn", target_age, "years old.")

# Stretch — years spent in school (assuming kindergarten started at age 5)
years_in_school = current_age - 5
print("You have spent about", years_in_school, "years in school so far.")

Yours can ask any extra questions you like. As long as you use input() three times and int() for the two ages, you've nailed it.

# greeter.py — ask the user some questions, then reply # 1. Ask for a name (a string is fine — no conversion needed) name = input("What is your name? ") # 2. Ask for age, then convert to int age_text = input("How old are you? ") age = int(age_text) # 3. Build a friendly response print() print("Selamat datang,", name + "!") print("Next year you'll be", age + 1, "— exciting!") # 4. A little maths on the answer months_alive = age * 12 print("You have been alive for roughly", months_alive, "months.")

# mamak_order.py — a friendly mamak calculator # 1. Ask the customer name = input("What's your name? ") roti_qty = int(input("How many roti canai? ")) teh_qty = int(input("How many teh tarik? ")) # 2. Prices and total roti_price = 2.00 teh_price = 2.50 total = roti_qty * roti_price + teh_qty * teh_price # 3. Receipt print() print("=" * 32) print(" Mamak Code — Order Receipt") print("=" * 32) print("Customer: ", name) print("Roti canai: ", roti_qty, "x RM", roti_price) print("Teh tarik: ", teh_qty, "x RM", teh_price) print("-" * 32) print("TOTAL: RM", total) print("=" * 32) # Stretch — split between friends friends = int(input("How many friends are sharing? ")) each_pays = total / friends print("Each person pays: RM", each_pays)

Listening to the User — input()

Learning Goals

Warm-Up

New Concept · Two-Way Conversations

Part 1 · The input() function

Part 2 · input() always gives back a string

Part 3 · Convert with int() and float()

Part 4 · Where to type your answer

Worked Example · A Personalised Greeter

The compact version

Asking for a decimal

Try It Yourself

Mini-Challenge · Mamak Order Calculator

Recap

Vocabulary Card

Homework

Sample · calc.py

Listening to the User — input()

Learning Goals

Warm-Up

New Concept · Two-Way Conversations

Part 1 · The input() function

Part 2 · input() always gives back a string

Part 3 · Convert with int() and float()

Part 4 · Where to type your answer

Worked Example · A Personalised Greeter

The compact version

Asking for a decimal

Try It Yourself

Mini-Challenge · Mamak Order Calculator

Recap

Vocabulary Card

Homework

Sample · calc.py