Input and Output

Learn how to display information to users and collect input from them so your Python programs can interact instead of always doing the same thing.

Skill Level: Beginner
Prerequisites: Variables, Data Types, Type Conversion, Built-in Functions
Estimated Time: 20 minutes

Story Time

Up to this point, each program you wrote produced the same result every time it ran. That is useful for practicing basics, but real programs rarely behave that way.

Interactive programs ask users questions, accept input, and respond based on what the user enters. This is the foundation of calculators, survey forms, small tools, and many data collection workflows.

In this lesson, you will learn how to display messages (output) and accept user responses (input) so your programs can begin to feel interactive.

What You’ll Learn

By the end of this lesson, you will be able to:

• Explain the difference between input and output.
• Display information using the print() function.
• Collect information from users using the input() function.
• Convert user input into appropriate data types.
• Build simple interactive Python programs.

What Is Output?

Output is information a program displays to the user.

In Python, output is usually displayed using the print() function.

print("Welcome to Python!")

Output:

Welcome to Python!

You will use output to show messages, results, and instructions.

Displaying Variables

Variables can also be displayed using print().

name = "Emma"
print(name)

Output:

Emma

You can print multiple values:

name = "Emma"
age = 22

print(name)
print(age)

Output:

Emma
22

Or combine values in a single print() call:

print(name, age)

What Is Input?

Input is information provided by the user while a program is running.

Python uses the input() function to collect user input:

name = input("Enter your name: ")
print(name)

Example interaction:

Enter your name: Emma
Emma

Here, the prompt ("Enter your name: ") helps the user understand what to type.

Storing User Input

You usually store the result of input() in a variable so you can use it later in your program.

city = input("Enter your city: ")
print(city)

Example:

Enter your city: Gainesville
Gainesville

Once stored, the value can be printed, combined with other text, or used in decisions later.

Understanding input()

One important rule:

input() always returns a string, even if the user enters digits.

age = input("Enter your age: ")
print(type(age))

Output:

<class 'str'>

That is why type conversion is often needed when working with user input.

Converting User Input

If you want to perform calculations, convert the input first.

age = int(input("Enter your age: "))
print(age + 1)

Example interaction:

Enter your age: 21
22

Now age is an integer, so addition works correctly.

Printing Multiple Values

Python allows multiple values inside print():

name = "Emma"
course = "Python"

print(name, course)

Output:

Emma Python

You can also combine text with variables:

name = "Emma"
print("Welcome", name)

Output:

Welcome Emma

Later in the course, you will learn more advanced formatting, but this simple pattern is enough for now.

Worked Example

name = input("What is your name? ")
age = int(input("How old are you? "))

print("Hello", name)
print("Next year you will be", age + 1)

Example interaction:

What is your name? Emma
How old are you? 22
Hello Emma
Next year you will be 23

This shows how input, conversion, and output can work together in a small interactive program.

Quick Check

Predict the output before running the code:

number = int(input("Enter a number: "))
print(number * 2)

What happens if the user enters:

5

Then test your prediction in Google Colab.

Practice in the Notebook

Notebook

Open in Google Colab

Practice this lesson in a live notebook.

After completing the activity in Google Colab, mark it as complete below.

Create a program that asks the user for:

• Name
• Favorite subject
• Age

Then display the information back to the user.

Example pattern:

name = input("Name: ")
subject = input("Favorite subject: ")
age = int(input("Age: "))

print("You are", name)
print("You enjoy", subject)
print("You are", age, "years old")

Try It Yourself

Write a program that asks the user for:

• University name
• Degree program
• Graduation year

Display the information in a readable format.

Example output:

University: University of Florida
Degree: Applied Data Science
Graduation Year: 2027

You can use multiple print() calls, or combine labels and variables in one call.

Challenge

Create a simple BMI information collector.

Ask the user for:

• Name
• Age
• Height (cm)
• Weight (kg)

Display the information in a neat format.

name = input("Name: ")
age = int(input("Age: "))
height_cm = float(input("Height (cm): "))
weight_kg = float(input("Weight (kg): "))

print("Name:", name)
print("Age:", age)
print("Height (cm):", height_cm)
print("Weight (kg):", weight_kg)

You do not need to calculate BMI yet. That will come later when you learn arithmetic operators.

Common Mistakes

Forgetting to convert numeric input

Incorrect:

age = input("Age: ")
print(age + 5)

This produces an error because age is a string.

Correct:

age = int(input("Age: "))
print(age + 5)

Forgetting quotation marks in prompts

Incorrect:

input(Enter your name)

Correct:

input("Enter your name")

Prompt text must be inside quotation marks so Python treats it as a string.

Forgetting to store the input

Incorrect:

input("Enter your city: ")

If you do not assign the result to a variable, you cannot use it later.

Correct:

city = input("Enter your city: ")

Now city can be printed, combined with other text, or used in later calculations.

Key Takeaways

• Output is information shown to the user, typically using print().
• Input is information provided by the user, collected with input().
• input() always returns a string, so numeric input must be converted before calculations.
• Combining print(), input(), and type conversion allows you to build simple interactive programs.

Self Evaluation

Check Your Understanding

1. What is output in a Python program?

Data stored in variablesInformation displayed to the userCode written by the programmerValues entered by the user

2. Which function is used to collect user input in Python?

print()len()input()type()

3. What data type does input() return by default?

intfloatstrbool

4. Which line correctly collects an age and allows arithmetic with it?

age = input("Age: ")age = int(input("Age: "))age = float("Age: ")age = print(input("Age: "))

5. Which example correctly stores and then prints the user’s city?

input("Enter your city: ") print(city)city = input("Enter your city: ") print(city)input("Enter your city: ") print(input)city = print("Enter your city: ")

Continue Your Journey

In the next lesson, you will learn about Collections, which allow Python to store multiple values together in structures such as lists.