Lecture 32:- if, else and elif In Python

In Python, if, else, and elif are conditional statements used to control the flow of a program based on certain conditions. These statements allow you to execute different blocks of code depending on whether specific conditions are met or not.

The syntax for these conditional statements is as follows:

1. if statement: The if statement is used to check a condition, and if the condition evaluates to True, the indented block of code under the if statement is executed. If the condition is False, the block of code is skipped.

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if condition:    # Code block to execute if the condition is True

1. else statement: The else statement is used in conjunction with the if statement. It provides an alternative block of code to execute when the condition of the if statement is False.

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

1. elif statement: The elif (short for "else if") statement is used to check additional conditions after the if statement. It allows you to test multiple conditions sequentially. If the condition of the if statement is False, Python will check the conditions specified by elif statements one by one until it finds a True condition. The corresponding block of code under the first True condition will be executed.

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if condition1:    # Code block to execute if condition1 is True elif condition2:    # Code block to execute if condition1 is False and condition2 is True elif condition3:    # Code block to execute if condition1 and condition2 are False, and condition3 is True ... else:    # Code block to execute if none of the conditions are True

Example:

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x = 10 if x > 0:    print("x is positive") elif x < 0:    print("x is negative") else:    print("x is zero")

In this example, the program checks the value of variable x and prints different messages based on its value. If x is greater than 0, it prints "x is positive." If x is less than 0, it prints "x is negative." Otherwise, if x is equal to 0, it prints "x is zero." The elif and else statements provide alternative conditions to be checked if the preceding conditions are not met.