Python If…Else

Conditional statements allow you to execute different blocks of code based on whether a condition is True or False. The primary conditional statements in Python are if, elif, and else.

If Statement

The if statement evaluates a condition, and if the condition is True, it executes the indented block of code that follows.

Explanation of Code:

The if statement is used to check a condition. If the condition is True, the code block under the if statement runs.

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

x = 10

if x > 5:

    print("x is greater than 5")

Elif Statement

The elif (else if) statement checks another condition if the previous if or elif condition was False.

Explanation of Code:

You can use multiple elif statements to check additional conditions if previous conditions are not met.

x = 10
if x > 15:
    print("x is greater than 15")
elif x > 5:
    print("x is greater than 5 but less than or equal to 15")

x = 10

if x > 15:

    print("x is greater than 15")

elif x > 5:

    print("x is greater than 5 but less than or equal to 15")

Else Statement

The else statement executes a block of code if none of the preceding if or elif conditions are True.

Explanation of Code:

The else block runs if all previous conditions are False.

x = 10
if x > 15:
    print("x is greater than 15")
elif x > 5:
    print("x is greater than 5 but less than or equal to 15")
else:
    print("x is less than or equal to 5")

x = 10

if x > 15:

    print("x is greater than 15")

elif x > 5:

    print("x is greater than 5 but less than or equal to 15")

else:

    print("x is less than or equal to 5")

Nested If Statements

You can nest if, elif, and else statements within each other to create complex conditional logic.

Explanation of Code:

Nested if statements allow you to check multiple conditions at different levels.

x = 10
y = 20
if x > 5:
    if y > 15:
        print("x is greater than 5 and y is greater than 15")
    else:
        print("x is greater than 5 but y is not greater than 15")
else:
    print("x is not greater than 5")

x = 10

y = 20

if x > 5:

    if y > 15:

        print("x is greater than 5 and y is greater than 15")

    else:

        print("x is greater than 5 but y is not greater than 15")

else:

    print("x is not greater than 5")

Python If…Else Example Code

Explanation of Code:

This program uses conditional statements to determine and print messages based on the value of the variable x.

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

# If...elif...else statement
if x > 15:
    print("x is greater than 15")
elif x > 5:
    print("x is greater than 5 but less than or equal to 15")
else:
    print("x is less than or equal to 5")

# Nested if statements
y = 20
if x > 5:
    if y > 15:
        print("x is greater than 5 and y is greater than 15")
    else:
        print("x is greater than 5 but y is not greater than 15")
else:
    print("x is not greater than 5")

# If statement

x = 10

if x > 5:

    print("x is greater than 5")

​

# If...elif...else statement

if x > 15:

    print("x is greater than 15")

elif x > 5:

    print("x is greater than 5 but less than or equal to 15")

else:

    print("x is less than or equal to 5")

​

# Nested if statements

y = 20

if x > 5:

    if y > 15:

        print("x is greater than 5 and y is greater than 15")

    else:

        print("x is greater than 5 but y is not greater than 15")

else:

    print("x is not greater than 5")

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