Understanding the Power of if-else Statements in Python

Introduction

In the world of programming, decision-making is a fundamental concept. Programs often need to perform different actions based on specific conditions. This is where conditional statements, such as if-else statements, come into play. In Python, the if-else statement is a powerful tool that allows developers to create dynamic and responsive code.

Anatomy of the if-else Statement

The if-else statement in Python is a conditional statement that allows you to execute different blocks of code based on whether a certain condition is true or false. The basic syntax looks like this:

if condition:
    # Code to be executed if the condition is true
else:
    # Code to be executed if the condition is false

Let's break down the components:

• if condition:: This is the main condition that the program evaluates. If it is true, the code block inside the if statement is executed. Otherwise, the code block inside the else statement is executed.

• else:: This part is optional. If the condition specified in the if statement is false, the code inside the else block will be executed.

Simple Examples

Example 1: Checking if a Number is Even or Odd

num = 7

if num % 2 == 0:
    print(f"{num} is even.")
else:
    print(f"{num} is odd.")

In this example, the program checks if the remainder of num divided by 2 is equal to 0. If it is, the number is even; otherwise, it's odd.

Example 2: Determining the Sign of a Number

number = -5

if number > 0:
    print(f"{number} is positive.")
elif number < 0:
    print(f"{number} is negative.")
else:
    print(f"{number} is zero.")

Here, the program checks whether a number is positive, negative, or zero using a combination of if, elif (else if), and else statements.

Nested if-else Statements

In Python, you can nest if-else statements inside one another. This allows for more complex decision-making logic.

x = 10

if x > 0:
    if x % 2 == 0:
        print(f"{x} is a positive even number.")
    else:
        print(f"{x} is a positive odd number.")
else:
    print(f"{x} is non-positive.")

In this example, the program first checks if x is positive. If it is, it further checks whether it's even or odd. If x is not positive, it prints that x is non-positive.

Ternary Conditional Expression

Python also supports a concise version of the if-else statement known as the ternary conditional expression.

result = "Even" if num % 2 == 0 else "Odd"
print(result)

This is equivalent to the first example but in a more compact form.

Conclusion

The if-else statement in Python is a versatile tool that enables developers to create dynamic and flexible programs. Whether it's handling simple conditions or complex decision trees, understanding how to use if-else statements is crucial for any Python programmer. As you delve deeper into programming, you'll find that mastering conditional statements is a key step toward writing efficient and responsive code.

Visit Codes with Pankaj for more insightful articles and tutorials on Python programming and other coding topics.

Question -

1. Write a Program to Check Whether a Number is Even or Odd.?

   Enter Number to Find Even or odd = 3

   -- Your Number 3 is Odd 

1. Write a Program to Check Whether an Alphabet is Vowel or Consonant ?

   Enter Alphabet : A

   -- A is Vowel 

1. Write a Program to Find the Largest Among Three Numbers ?
   

   Enter Number 1 : 100
   Enter Number 2 : 300
   Enter Number 3 : 400 
   -- Number 300 is Largest 
   

2. Write a Program to Check Leap Year ?
   

   Enter Year : 2023 
   

-- 2023 is not Leap Year

5. Write a program to find Grade ?



   ```yaml
   Example : Grading System 
   80 - 100 = Grade A
   60 - 80 = Grade B
   40 - 60 = Grade C
   30 - 40 = Grade D
   0  - 30 Grade F

1. Find Age ?

   -- Date of birth Section 

   Enter Your Birth Year : 1992
   Enter Your Birth Month : 4
   Enter Your Birth Day : 16

   -- Current Date

   Enter Your Current Year : 2023
   Enter Your Current Month : 7
   Enter Your Current Day : 26 

   -- output

   30 years 3 months 10 days
   or 363 months 10 days
   or 1579 weeks 5 days
   or 11,058 days
   or 265,392 hours

1. Password Checker Example :

   Set your password :
   p4n@in
   Enter your Password : 
   p4n
   wrong password ... try 2 more time out of 2
   p4n@
   wrong password ... try 1 more time 1
   p4n@34
   wrong password ... try 0 more time 0
   note : user select right password
   then start MCQ EXAM...


   1. Who invented Java Programming?
   1. ) Guido van Rossum
   2. ) James Gosling
   3. ) Dennis Ritchie
   4. ) Bjarne Stroustrup

   Select Answer 2

   wrong answer [ Try Next year ] 

   Note :if select Right Answer 
   ask 2nd Question ...

   2. Which component is used to compile, debug and execute the java programs?
   1. ) JRE
   2. ) JIT
   3. ) JDK
   4. ) JVM

   Select Answer 2 ... con..

1. Student Report Card System

---- Input Section
Enter your name : Joy
Enter Your Roll Number : A1023

Enter Your JAVA Marks : 50
Enter Your C++ Marks : 20
Enter Your go Marks : 25
Enter Your Ruby Marks : 96
Enter Your C# Marks : 70
Enter Your Python Marks : 65

---- Output Section
JAVA = 50/100 
C++ = 20/100 F
go = 25/100 F
Ruby = 96/100
C# = 70/100
Python = 65/100

Total = 326/600
per = 54% FAIL
IF PASS
Grading System 
80 - 100 = Grade A
60 - 80 = Grade B
40 - 60 = Grade C
30 - 40 = Grade D