How to Use If-elif-else Statements in Python: A Comprehensive Guide || @dev_code

Dev Mallik

How to Use If-elif-else Statements in Python: A Comprehensive Guide ...

Control of flow in Python...

The video covers the following topics:

   - Explanation of if, elif, and else statements in Python.
   - Syntax and usage of if, elif, and else statements.
   - Examples of if, elif, and else statements in Python.
   - Best practices for using if, elif, and else statements in         Python.

Python is a popular programming language that is widely used for various applications such as web development, scientific computing, data analysis, and machine learning. One of the key features of Python is its ability to make decisions based on certain conditions using the if-elif-else statements. In this blog post, we will discuss how to use if-elif-else statements in Python, and provide examples of their usage.

The if Statement:
The if statement is used to execute a block of code if a certain condition is true. The general syntax of the if statement in Python is as follows:


if (string == string[::-1]):
    return "The string is a palindrome."

Here, the condition is any expression that evaluates to a Boolean value, i.e., either True or False. If the condition is True, the code block below the if statement is executed. If the condition is False, the code block is skipped.

Example:

# Check if a number is even or odd
num = 5
if num % 2 == 0:
    print("The number is even")"

In this example, the condition num % 2 == 0 checks if the number num is divisible by 2 without a remainder. Since 5 % 2 is not equal to 0, the code block below the if statement is skipped, and nothing is printed.

The elif Statement:
The elif statement is used to test additional conditions after the if statement. If the if statement is False, the elif statement is checked. If the elif statement is True, the code block below it is executed, and the remaining elif statements are skipped. The general syntax of the elif statement in Python is as follows:

if condition1:
    # execute this block of code if condition1 is true.
elif condition2:
    #execute this block of code if condition2 is true.
elif condition3:
    #execute this block of code if condition3 is true.
else:
    # execute this block of code if all conditions are false.

Here, we can have multiple elif statements, but only one else statement. The elif statements are checked in order until a True condition is found. If all the conditions are False, the else statement is executed.

Example:

# Check if a number is positive, negative or zero
num = -2
if num > 0:
    print("The number is positive.")
elif num < 0:
    print("The number is negative.")
else:
    print("The number is zero.")

In this example, the condition num > 0 checks if the number num is greater than 0. Since num is negative, the condition is False. The next elif statement checks if num is less than 0, which is True, so the code block below it is executed. Therefore, the output of this code is "The number is negative".

The else Statement:

The else statement is used to execute a block of code if all the conditions in the if-elif-else chain are False. The general syntax of the else statement in Python is as follows:

if condition:
    # execute this block of code if condition is true.
else:
    # execute this block of code if condition is false.

Example:

# Check if a number is even or odd
num = 5
if num % 2 == 0:
    print("The Number is Even.")
else:
    print("The Number is Odd.")

In this example, the condition num % 2 == 0 checks if the number num is divisible by 2 without a remainder. Since 5 % 2 is not divided by 2 it will read the else condition and will print("The number is odd.").

 

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