Python If Else Statements – Conditional Statements with Examples

Python if-else statements are used extensively in decision-making code. In real-world applications, there are numerous cases where you must run a certain group of code depending on certain conditions. These statements will help you write logical and efficient code as well as assist you in managing user inputs, validating data, and controlling programs. Here in this article, you will see various ways to implement if-else statements in Python with real-time examples with step-by-step illustrations.

Table of Contents:

• Python Conditional Statements
  • If Statement in Python
  • If…Else Statement in Python
  • If…Elif…Else Statement in Python
  • Nested if Statement in Python
• Shorthand If and If…Else in Python
• Logical Operators with If…Else Statements in Python
• Using If…Else Statements Inside Functions in Python
• Working with If…Else Statements in Loops
  • Using If…Else in a For Loop
  • Using If…Else in a While Loop
• Best Practices for Using If Statements in Python
• Comparison of Conditional Statements in Python
• Real-World Examples of the If…Else Statement in Python
• Conclusion

Python Conditional Statements

In Python, conditional statements control the flow of a program by making decisions based on the given conditions. These statements help in determining the execution of the programs by evaluating the conditions, such as True or False. This helps in making the Python program more interactive, as it responds to different situations automatically and returns the output. Adding conditional statements to your Python code is necessary to control the program flow and improve the process of decision-making, which makes the code organized and efficient.

There are 4 types of conditional statements in Python:

• if statement
• if-else statement
• if-elif-else statement
• Nested if statement

1. If Statement in Python

The if statement checks a condition and executes the code only if the condition is True and does not return any output if the condition is False. It is very useful for controlling the flow of the program and helps ensure that the specific code runs only when it is needed.

Syntax:

if condition:
# Code to execute if the condition is True
# This block runs only when the condition is met

Example:

Output:

Explanation: Here, the program checks if the age is greater than or equal to 16, prints a message if the condition is true, and does not return any output if the condition is False.

2. If…Else Statement in Python

The if-else statement runs one block of code if the condition is True and another if the condition does not match and is False. This ensures that the Python programs return some statements.

The following flowchart will show you how the If…Else statement in Python works:

Syntax:

if condition:
# Statement executes if the condition is True
else:
# Statement executes if the condition is False

Example:

Output:

Explanation: Here, it is checked whether the marks are equal to or more than 60, and prints the message only if the condition is satisfied.

3. If…Elif…Else Statement in Python

The if-elif-else statement checks multiple conditions one after the other and executes the condition that is satisfied first and is true. It is useful if there is a possibility of multiple results.

Syntax:

if condition1:
# Code executes if condition1 is True
elif condition2:
# Code executes if condition1 is False and condition2 is True
else:
# Code executes if neither condition1 nor condition2 is True

Example:

Output:

Explanation: Here, different messages are assigned based on the value of the score.

4. Nested if Statement in Python

A nested if statement is an if statement inside another if. It is used when multiple conditions should be met and returns the statement only if all the conditions are satisfied.

Syntax:

if condition1:
if condition2:
# Statement if both conditions are True

Example:

Output:

Explanation: Here, it is checked if the age of the user is more than 16,  then confirms course registration before displaying the message.

Shorthand If and If…Else in Python

Shorthand if and if-else is nothing but a way to write the if and the else block without any indentation in a single line. This is very useful when we have only one statement to be executed in the if block and the else block.

Shorthand If Syntax:

# Syntax for a shorthand if statement
if condition: statement

Example:

Explanation: Here, if the completion_percentage is more than 80 percent, then the message is printed.

Shorthand If…Else Syntax:

# Syntax for a shorthand if-else statement
statement_if_true if condition else statement_if_false

Example:

Output:

Explanation: Here, if marks are 60 or more, it prints “Congratulations! You passed the Intellipaat exam!”. Otherwise, it prints “Keep learning and try again!”.

Logical Operators with If…Else Statements in Python

Logical operators help to combine multiple conditions in if-else statements, which makes the decision-making more flexible. They allow checking multiple conditions at once instead of writing separate if statements.

1. Using ‘and’ Logical Operator with If-Else in Python

The and keyword is used when multiple conditions need to be checked. It makes sure that, to execute the statement, both conditions must be true. If any condition is False, it returns another statement.

Example:

Output:

Explanation: Here, the and operator ensures that both conditions (num > 10 and num < 20) must be True.

2. Using or Logical Operator with If…Else in Python

The or keyword is used when at least one of the conditions mentioned is True. If any condition is True, the block under it is executed. If both conditions are False, the other statement, which is given inside the else block, is executed.

Example:

Output:

Explanation: Here, the ‘or’ operator checks if at least one condition is True. Since num is less than 10, the statement is executed, even though num is not greater than 50.

3. Using not Logical Operator with If…Else in Python

The not keyword is used to reverse a condition. If the condition is True, then this keyword makes it False. This is useful when checking for the opposite of a condition.

Example:

Output:

Explanation: Here, the not operator gives the condition num > 0. Since num is not greater than 0, the statement under the if is executed successfully.

Using If…Else Statements Inside Functions in Python

Using if-else statements inside Python functions makes the code more structured, reusable, and efficient. Functions allow you to encapsulate logic and execute conditional checks based on user input or given values.

Example:

Output:

Explanation: Here, the function check_voting_eligibility(age) checks if the age of the voter is greater than or equal to 18 and prints the eligibility status.

Working with If…Else Statements in Loops

If-Else statements inside loops allow decision-making during each iteration, which helps to execute different blocks of code based on conditions.

Using If…Else in a For Loop

A for loop runs a block of code a fixed number of times, and if-else inside it checks conditions for each iteration.

Example:

Output:

Explanation: The loop runs from 1 to 5. The if condition checks whether the number is even or odd and prints the result accordingly.

Using If…Else in a While Loop

A while loop runs repeatedly as long as a condition is True, and if-else inside it helps make decisions during each iteration.

Example:

Output:

Explanation: The loop starts at 5 and decreases until it reaches 0, printing a different message for zero.

Best Practices for Using If Statements in Python

• Use Proper Indentation: Always keep code within if, elif, and else properly indented, which helps to prevent mistakes and increase the readability.
• Keep Conditions Simple: Complex conditions should not be used, and always try to break the condition into smaller parts to make it simple to understand the condition.
• Use elif instead of Multiple if: When there are multiple conditions to be checked, elif has to be used so that the checking can be stopped once the condition is matched.
• Include else: The else statement has to be added to return some message when the condition is not True.
• Use Boolean Variables: A proper variable name has to be given for the True or false condition. You can use marks when you are adding marks instead of the variables x and y, which helps in improving the readability.

Comparison of Conditional Statements in Python

Real-World Examples of the If…Else Statement in Python

The Python If…Else statement is used in many real-world cases. Now let’s see some of the most common use cases of it.

1. Checking Exam Results

Output:

Explanation: If the marks are greater than or equal to 60, it prints a pass message. Otherwise, it prints a fail message.

2. Checking Login Credentials

Output:

Explanation: If both the username and password match, the login is successful. Otherwise, it fails.

3. ATM Cash Withdrawal

Output:

Explanation: If the withdrawal amount is less than or equal to the balance, the transaction proceeds; Otherwise, it fails.

Conclusion

The Python if-else statement is essential in controlling program flow and decision making. It is important to use the conditional operators like if statements, if-elif-else blocks, and shorthand expressions, which can be used to write simple 1 line statements along with the condition to write a clean, efficient, and organized Python Code. Learn these conditional statements thoroughly, and you will be able to write logic in different situations and improve the logic of your program.

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