Python Conditional Statements

Conditional statements in Python allow you to execute different blocks of code based on certain conditions. They are fundamental for making decisions in your programs and controlling the flow of execution.

1. if Statement

The if statement evaluates a condition and executes a block of code if the condition is True.

Basic Syntax:

if condition:
    # Code block to execute

Example:

x = 10
if x > 5:
    print("x is greater than 5")

Output:

x is greater than 5

Explanation:

• The condition x > 5 is True, so the code block inside the if statement is executed.

2. if-else Statement

The if-else statement allows you to execute one block of code if the condition is True, and a different block if the condition is False.

Basic Syntax:

if condition:
    # Code block to execute if condition is True
else:
    # Code block to execute if condition is False

Example:

x = 3
if x > 5:
    print("x is greater than 5")
else:
    print("x is 5 or less")

Output:

x is 5 or less

Explanation:

• The condition x > 5 is False, so the code block in the else statement is executed.

3. if-elif-else Statement

The if-elif-else statement allows you to check multiple conditions in sequence. If the first condition is False, the next elif condition is checked, and so on. If none of the conditions are True, the else block is executed.

Basic Syntax:

if condition1:
    # Code block to execute if condition1 is True
elif condition2:
    # Code block to execute if condition1 is False and condition2 is True
else:
    # Code block to execute if all conditions are False

Example:

x = 7
if x > 10:
    print("x is greater than 10")
elif x > 5:
    print("x is greater than 5 but not greater than 10")
else:
    print("x is 5 or less")

Output:

x is greater than 5 but not greater than 10

Explanation:

• The first condition x > 10 is False, so the elif condition x > 5 is checked and found to be True. The corresponding code block is executed.

4. Nested Conditional Statements

You can nest if, elif, and else statements inside each other to handle more complex conditions.

Example:

x = 15
if x > 10:
    if x > 20:
        print("x is greater than 20")
    else:
        print("x is greater than 10 but not greater than 20")
else:
    print("x is 10 or less")

Output:

x is greater than 10 but not greater than 20

Explanation:

• The outer if condition x > 10 is True, so the nested if-else statement is evaluated. The nested condition x > 20 is False, so the corresponding else block is executed.

5. Ternary Operator (Conditional Expression)

Python supports a shorthand for if-else statements known as the ternary operator. It allows you to assign values based on a condition in a single line.

Basic Syntax:

value = true_value if condition else false_value

Example:

x = 10
result = "Even" if x % 2 == 0 else "Odd"
print(result)

Output:

Even

Explanation:

• The condition x % 2 == 0 checks if x is even. Since it is true, result is assigned "Even".

6. Conditional Statements with Multiple Conditions

You can combine multiple conditions using logical operators like and, or, and not.

Example:

x = 15
y = 20
if x > 10 and y < 25:
    print("Both conditions are met")
else:
    print("One or both conditions are not met")

Output:

Both conditions are met

Explanation:

• Both conditions x > 10 and y < 25 are True, so the code block inside the if statement is executed.

Conclusion

Conditional statements in Python are powerful tools for making decisions and controlling the flow of execution in your programs. By understanding how to use if, if-else, and if-elif-else statements, as well as nested conditions and the ternary operator, you can write more dynamic and flexible code.