Input is data that a user gives to a program.
Example:
✅ Output
Output is the result the program shows to the user.
Example:
Taking Input in Python
Python uses the input() function.
name = input("Enter your name: ")
print(name)
What happens?
⚠️ Important: Input is Always a String
age = input("Enter your age: ")
print(age)
Even if you type 25, Python stores it as "25".
Converting Input to Other Data Types
age = int(input("Enter your age: "))
height = float(input("Enter your height: "))
Type Conversion Table
| Function | Converts To | Example |
|----------|------------|---------|
int() | Integer | int("5") → 5 |
float() | Decimal number | float("3.5") → 3.5 |
str() | String | str(10) → "10" |
Output in Python
Python uses the print() function.
print("Hello World")
Printing Variables
name = "Danny" print(name)
Printing Multiple Items
name = "Danny" age = 25 print(name, age)
Default Separator = Space
Output:
Danny 25
Custom Separator
print("Python", "Java", "C++", sep=" | ")
Output:
Python | Java | C++
Custom End Character
print("Hello", end=" ")
print("World")
Output:
Hello World
Formatting Output (Very Important)
✅ Using f-strings (Best Method)
name = "Danny"
score = 95
print(f"My name is {name} and I scored {score}")
✅ Using format()
print("My name is {} and I scored {}".format(name, score))
✅ Using % formatting (Old method)
print("My name is %s and I scored %d" % (name, score))
Output Formatting Methods
| Method | Example | Result |
|--------|---------|--------|
f-string | f"{name}" | Danny |
format() | "{}".format(name) | Danny |
% operator | "%s" % name | Danny |
Printing Special Characters
Escape Characters
| Escape | Meaning | |--------|---------| \n | New line | \t | Tab space | \" | Double quote | \' | Single quote | \\ | Backslash |
Example:
print("Hello\nWorld")
Output:
Hello World
Taking Multiple Inputs
Method 1: Separately
a = input("Enter first number: ")
b = input("Enter second number: ")
Method 2: In One Line
a, b = input("Enter two numbers: ").split()
For numbers:
a, b = map(int, input("Enter two numbers: ").split())
Examples
✅ Example 1: Simple Calculator
num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))
sum = num1 + num2
print("The sum is:", sum)
✅ Example 2: Student Details
name = input("Enter your name: ")
age = int(input("Enter your age: "))
print(f"Student name is {name} and age is {age}")
✅ Example 3: Temperature Converter
celsius = float(input("Enter temperature in Celsius: "))
fahrenheit = (celsius * 9/5) + 32
print(f"Fahrenheit: {fahrenheit}")
⚠️ Common Beginner Mistakes
| Mistake | Why It Happens | Solution | |----------|---------------|----------| Adding numbers without int() | Input is string | Convert using int() | Forgetting quotes in print | Text must be string | Use " " | Wrong variable order | Logic error | Check variable placement |
Summary
| Concept | Function | Example |
|----------|-----------|----------|
User input | input() | input("Enter name: ") |
Display output | print() | print("Hello") |
Convert to int | int() | int(input()) |
Convert to float | float() | float(input()) |
Formatted output | f-string | f"{name}" |
Multiple input | split() | input().split() |
Tip
Flow of a Python Program:
INPUT → PROCESS → OUTPUT
Example:
num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))
result = num1 + num2
print("Answer is:", result)