Python Input & Output

What Is Input & Output?

Input and output are fundamental parts of almost every useful program.

Input means receiving information from a user or another source.

Output means displaying or producing information for the user or another system.

name = input("What is your name? ")

print("Hello", name)

What is your name? Ali
Hello Ali

The print() Function

The print() function is used to display information on the screen.

Basic Example

print("Hello, Python!")

Hello, Python!

You can print text, numbers, variables, calculations, and many other Python objects.

Printing Different Values

The print() function can display different types of values.

print("Python")
print(100)
print(3.14)
print(True)

name = "Ahmed"
print(name)

Python
100
3.14
True
Ahmed

Printing an Expression

print(10 + 20)
print(50 * 2)

30
100

Printing Multiple Values

You can pass multiple values to print(). Python separates them with a space by default.

name = "Ali"
age = 25

print("Name:", name, "Age:", age)

Name: Ali Age: 25

This is useful when you want to combine several pieces of information in one output statement.

The sep Parameter

The sep parameter controls what appears between multiple values passed to print().

Default Separator

print("Python", "Java", "C++")

Python Java C++

Custom Separator

print("2026", "09", "12", sep="-")

2026-09-12

You can use almost any string as the separator.

print("A", "B", "C", sep=" | ")

A | B | C

The end Parameter

By default, print() moves to a new line after displaying its output.

print("Hello")
print("World")

Hello
World

The end parameter allows you to change what happens at the end of the output.

print("Hello", end=" ")
print("World")

Hello World

Using end with a Symbol

print("Loading", end="...")
print("Done")

Loading...Done

Formatting Output

Good output should be easy for the user to understand. Python gives you several ways to combine text and values.

Using Commas

name = "Sara"
score = 95

print("Student:", name, "Score:", score)

Student: Sara Score: 95

Using String Concatenation

name = "Sara"

print("Hello " + name)

Hello Sara

The input() Function

The input() function allows a Python program to receive information from the user.

name = input("Enter your name: ")

print(name)

Enter your name: Ahmed
Ahmed

When Python reaches input(), it pauses and waits for the user to type something and press Enter.

Storing User Input

Usually, we store user input inside a variable so we can use it later.

name = input("What is your name? ")
city = input("Where do you live? ")

print("Name:", name)
print("City:", city)

What is your name? Ali
Where do you live? Multan
Name: Ali
City: Multan

Once stored, the values can be used multiple times.

Converting User Input

Because input() returns a string, numeric input usually needs to be converted before calculations.

Integer Input

age = int(input("Enter your age: "))

print(age)

Floating-Point Input

price = float(input("Enter price: "))

print(price)

Boolean Input

Be careful when converting strings directly with bool().

print(bool("False"))

True

The string "False" is not an empty string, so it evaluates to True.

Working with Multiple Inputs

You can collect several pieces of information from a user using separate input() calls.

name = input("Name: ")
age = int(input("Age: "))
city = input("City: ")

print("Name:", name)
print("Age:", age)
print("City:", city)

Name: Hamza
Age: 22
City: Lahore

Each input can be converted independently depending on the type of information expected.

Input and Calculations

Once numeric input has been converted, it can be used in mathematical expressions.

Adding Two Numbers

num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))

total = num1 + num2

print("Total:", total)

Enter first number: 15
Enter second number: 25
Total: 40

Calculating a Rectangle Area

length = float(input("Enter length: "))
width = float(input("Enter width: "))

area = length * width

print("Area:", area)

Enter length: 10
Enter width: 5
Area: 50.0

Input with f-Strings

F-strings provide a clean and readable way to insert variables into strings.

name = input("Enter your name: ")
age = int(input("Enter your age: "))

print(f"Hello {name}, you are {age} years old.")

Enter your name: Sara
Enter your age: 24
Hello Sara, you are 24 years old.

F-strings are especially useful when creating readable messages containing multiple variables.

Escape Characters

Escape characters allow you to represent special formatting inside strings.

New Line: \n

print("Hello\nWorld")

Hello
World

Tab: \t

print("Name:\tAli")

Name:   Ali

Quotation Marks

print("He said \"Hello\"")

He said "Hello"

Common Input & Output Mistakes

Mistake 1: Forgetting Input Is a String

age = input("Age: ")

print(age + 5)

This produces a TypeError because age is a string.

Correct:

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

print(age + 5)

Mistake 2: Concatenating a Number Directly

age = 25

print("Age: " + age)

The string and integer cannot be concatenated directly.

Use an f-string:

age = 25

print(f"Age: {age}")

Mistake 3: Invalid Numeric Input

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

If the user enters twenty instead of 20, Python raises a ValueError.

Practice Exercises

print("Python", "is", "awesome", sep="-")

Mini Challenge

Student: Ali
Total Marks: 255
Average: 85.0

Quick Knowledge Check

Test your understanding of Python input and output.

Lesson Summary

Input and output allow Python programs to communicate with users and make programs interactive.