Programming is all about making decisions, and Python equips you with the tools to make those decisions effectively. In Python, control structures like conditional statements (if, else, elif) play a pivotal role in directing the flow of your programs. In this article, we’ll delve deep into Python’s conditional statements, providing you with real-world examples and their corresponding outputs. Conditional statements, including if, else, and elif, are essential tools in Python programming. They allow your code to make decisions based on specific conditions, enabling you to create versatile and interactive programs.
Understanding Conditional Statements
Conditional statements allow your Python programs to take different paths depending on certain conditions. The primary conditional statements in Python are if, else, and elif (short for “else if”). These statements evaluate expressions and execute specific code blocks based on the results.
The ‘if’ Statement
The if statement is used to execute a block of code if a condition is met. Here’s a basic example:
age = 18
if age >= 18:
print("You are eligible to vote.")
In this example, the condition age >= 18 is true, so the message “You are eligible to vote.” will be printed.
The ‘else’ Statement
The else statement works in conjunction with if and is used to specify what to do if the if condition is not met. Consider this example:
age = 15
if age >= 18:
print("You are eligible to vote.")
else:
print("You are not eligible to vote yet.")
Since the condition age >= 18 is false, the program will print “You are not eligible to vote yet.”
The ‘elif’ Statement
The elif statement is short for “else if” and allows you to evaluate multiple conditions sequentially. This is helpful when you have more than two possible outcomes. Here’s an example:
score = 75
if score >= 90:
print("A")
elif score >= 80:
print("B")
elif score >= 70:
print("C")
else:
print("D")
In this case, since the score is 75, the program will print “C.”
Examples
Now, let’s explore some real-world examples to demonstrate the power of conditional statements in Python.
Example 1: Checking for Even or Odd
number = 7
if number % 2 == 0:
print(f"{number} is even.")
else:
print(f"{number} is odd.")
Output: 7 is odd.
Example 2: Determining Leap Years
year = 2024
if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0):
print(f"{year} is a leap year.")
else:
print(f"{year} is not a leap year.")
Output: 2024 is a leap year.
Example 3: Handling User Input
user_input = input("Enter your age: ")
age = int(user_input)
if age >= 18:
print("You are eligible to access this content.")
else:
print("Sorry, you are not eligible to access this content.")
In this last example, the program will ask the user for their age and provide access based on the input.
