Introduction to Conditionals in Python

In programming, conditionals are used to perform different actions based on different conditions. In Python, the if statement is used to implement conditionals.

Syntax of the if statement

The syntax of the if statement in Python is as follows:

if condition:
    statement(s)

Here, condition is the condition that we want to check, and statement(s) is the action that we want to perform if the condition is true.

Example

Let's consider a simple example where we want to print a message if a variable x is greater than 10:

x = 12

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

In this example, the condition x > 10 is true (since x is 12), so the message "x is greater than 10" will be printed.

if...else statement

Sometimes, we want to perform one action if the condition is true, and a different action if the condition is false. In such cases, we can use the if...else statement in Python.

The syntax of the if...else statement is as follows:

if condition:
    statement(s) if condition is true
else:
    statement(s) if condition is false

Here, condition is the condition that we want to check, and statement(s) are the actions that we want to perform based on whether the condition is true or false.

Example

Let's consider an example where we want to print a message if a variable x is greater than 10, and a different message if it is not:

x = 8

if x > 10:
    print("x is greater than 10")
else:
    print("x is not greater than 10")

In this example, the condition x > 10 is false (since x is 8), so the message "x is not greater than 10" will be printed.

if...elif...else statement

In some cases, we may want to perform different actions based on multiple conditions. In such cases, we can use the if...elif...else statement in Python.

The syntax of the if...elif...else statement is as follows:

if condition1:
    statement(s) if condition1 is true
elif condition2:
    statement(s) if condition2 is true
else:
    statement(s) if all conditions are false

Here, condition1, condition2, etc. are the conditions that we want to check in order. The first condition that is true will trigger the corresponding action(s). If none of the conditions are true, the else statement will perform its corresponding action(s).

Example

Let's consider an example where we want to print a message based on the value of a variable x:

x = 3

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

In this example, since x is 3, the second condition (x > 0) is true, so the message "x is positive" will be printed.