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🌱 Beginner

Python User Input – The input() Function Explained

Programs that can only run with hardcoded values are not very useful. The input() function lets your Python program communicate with the user — asking for information and responding to it. This is how you make your programs interactive.

⏱️ 18 min read 🎯 Beginner 📅 Updated 2026

The input() Function – Basics

The input() function pauses your program, displays a prompt, waits for the user to type something and press Enter, then returns what they typed as a string.

Python
# Basic input
name = input("What is your name? ")
print(f"Hello, {name}!")
▶ Output
What is your name? Alice Hello, Alice!

Always Returns a String – Type Conversion Required

This is the most common mistake: input() ALWAYS returns a string, even if the user types a number. You must convert it to the right type.

Python
# ❌ Bug: comparing string to integer
age = input("Enter your age: ")   # Returns "25" (string)
if age > 18:  # Error! Can't compare str > int
    print("Adult")

# ✅ Correct: convert to int first
age = int(input("Enter your age: "))  # Now it's an integer
if age > 18:
    print("Adult")
▶ Output
Adult
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Converting Input to Different Types

Use int(), float(), or other conversion functions wrapped around input() to get the type you need.

Python
name = input("Name: ")              # str - no conversion needed
age = int(input("Age: "))            # int
price = float(input("Price: $"))     # float
active = input("Active? (y/n): ") == "y"  # bool

print(type(name), type(age), type(price), type(active))
▶ Output

Input Validation – Handling Bad Input

Users type unexpected things. Always validate input when your program depends on a specific format.

Python
# Keep asking until valid number given
while True:
    try:
        age = int(input("Enter age (0-120): "))
        if 0 <= age <= 120:
            break
        print("Age must be between 0 and 120.")
    except ValueError:
        print("Please enter a valid number.")

print(f"Your age is: {age}")
▶ Output
Enter age (0-120): abc Please enter a valid number. Enter age (0-120): -5 Age must be between 0 and 120. Enter age (0-120): 25 Your age is: 25

Getting Multiple Inputs

You can get multiple values in one line using split(), or ask separately.

Python
# Option 1: separate inputs
first = input("First name: ")
last = input("Last name: ")

# Option 2: one line, split by space
x, y = input("Enter two numbers (space-separated): ").split()
x, y = int(x), int(y)
print(f"Sum: {x + y}")
▶ Output
Enter two numbers (space-separated): 10 20 Sum: 30
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