Conditional Statements - Part 09

Welcome to the Python Chronicles! In this lesson, we will learn about the concept of conditional statements, which allow us to make decisions and control the flow of our programs. Conditional statements are useful for creating programs that can perform different actions based on certain conditions. By the end of this lesson, you will have a solid understanding of if, else, and elif statements and be able to use them effectively in your programs. So, let's get started!

Understanding Conditions

Before we learn the conditional statements, let's understand what conditions are. A condition is an expression that evaluates to either True or False. Based on the result of a condition, we can decide whether to execute certain blocks of code or not. Conditions are typically created using comparison operators, such as == (equal to), != (not equal to), > (greater than), < (less than), >= (greater than or equal to), and <= (less than or equal to).

1.The if Statement

The if statement is the most basic conditional statement. It allows us to execute a code only if a certain condition is True.

In the example above, the code block is executed only if the age is both greater than or equal to 18 and less than or equal to 30.

2.The else Statement

The else statement is used in conjunction with the if statement. It allows us to specify a block of code to be executed if the condition of the if statement is False.

In the example above, if the age is less than 18, the condition of the if statement is False, and the code block under the else statement is executed, printing the message "You are not eligible to vote."

3.The elif Statement

The elif statement, short for "else if," allows us to check multiple conditions. It is used when we have more than two possible outcomes.

In the example above, if the grade is greater than or equal to 90, the message "Excellent!" is printed. If the grade is between 70 and 89, the message "Good job!" is printed. Otherwise, the message "You need to improve." is printed.

4.Nested if Statements

Conditional statements can also be nested, meaning one conditional statement can be placed inside another. This allows for more complex decision-making.

In the example above, we have a nested if statement. If the age is greater than or equal to 18, we check if it is less than or equal to 65. Based on the result, we print different messages.

Logical Operators

1.AND Operator

The and operator returns True if both conditions on either side of the operator are True.

In the example above, the code block is executed only if the age is both greater than or equal to 18 and less than or equal to 30.

2. OR Operator

The or operator returns True if at least one of the conditions on either side of the operator is True.

In the example above, the code block is executed if the day is either "Saturday" or "Sunday."

3. NOT Operator

The not operator returns the opposite of the condition's result. If a condition is True, the not operator will return False, and vice versa.

In the example above, the code block is executed only if the age is not greater than or equal to 18, meaning the person is too young to vote.

Conclusion

In this lesson, we learned the concept of conditional statements in Python. We learned how to use the if, else, and elif statements to make decisions based on certain conditions. We also discovered how to make  nest if statements, use logical operators to combine conditions, and perform different actions based on the type of conditions. Understanding conditional statements is essential for creating programs that can adapt and make decisions based on special situations. Keep practicing and experimenting with conditional statements to boost your understanding. Happy coding!