Programming is all about making decisions, and Python provides powerful tools to implement decision-making in your code. In this article, we will explore three essential components for making decisions in Python: the
if statement, the
else statement, and the
elif statement. Understanding how these statements work will enable you to create dynamic and responsive programs that handle different scenarios effectively.
Table of Contents
if else Statement
if statement is the most fundamental conditional statement in Python. It allows you to execute a block of code only if a specific condition is true. The syntax of the
if statement is straightforward:
if condition: # Code block to execute if the condition is True
The code block under the
if statement will only be executed if the condition specified evaluates to
True. If the condition is
False, the code block will be skipped.
x = 10 if x > 5: print("x is greater than 5")
In this example, the code block will be executed because the condition
x > 5 is true (
x is 10).
else statement is used in conjunction with the
if statement to specify an alternative code block to be executed when the
if condition is false. The syntax is as follows:
if condition: # Code block to execute if the condition is True else: # Code block to execute if the condition is False
The code block under the
else statement will be executed only if the condition specified in the
if statement is
x = 3 if x > 5: print("x is greater than 5") else: print("x is not greater than 5")
In this example, since
x is 3 and the condition
x > 5 is false, the code block under the
else statement will be executed, and the output will be “x is not greater than 5.”
elif statement is short for “else if” or “if else” and is used when you have multiple conditions to check. It allows you to specify additional conditions to be evaluated if the previous conditions are false. The syntax is as follows:
if condition1: # Code block to execute if condition1 is True elif condition2: # Code block to execute if condition2 is True elif condition3: # Code block to execute if condition3 is True # Add more elif blocks as needed else: # Code block to execute if all conditions are False
Python will evaluate each condition in order, and as soon as it finds a condition that is true, it will execute the corresponding code block and skip the rest of the
x = 10 if x > 15: print("x is greater than 15") elif x > 5: print("x is greater than 5 but not greater than 15") else: print("x is not greater than 5")
In this example, since
x is 10, the condition
x > 5 is true, so the code block under the corresponding
elif statement will be executed, and the output will be “x is greater than 5 but not greater than 15.”
Also read : What are strings in python
let’s dive deeper into
elif statements with more examples.
In Python, you can also nest
if statements inside other
if statements. This allows you to create more complex decision-making logic.
x = 10 if x > 5: print("x is greater than 5") if x > 8: print("x is also greater than 8")
In this example, the first
if statement checks if
x is greater than 5. If the condition is true, it executes the corresponding code block and then proceeds to check if
x is greater than 8 using the nested
if statement. If this condition is also true, it will print “x is also greater than 8.”
Multiple Conditions with
elif or if else statements are particularly useful when you have multiple conditions to check. You can chain multiple
elif statements after the initial
if statement to cover various scenarios.
age = 25 if age < 18: print("You are a minor") elif age >= 18 and age < 65: print("You are an adult") else: print("You are a senior citizen")
In this example, the code checks the value of the variable
age and prints the appropriate message based on whether the person is a minor, an adult, or a senior citizen.
Python utilizes short-circuit evaluation to optimize
if else statements with multiple conditions. In a logical expression involving
and, if the first condition is
False, Python will not evaluate the remaining conditions, as the overall result will be
False. Similarly, in a logical expression involving
or, if the first condition is
True, Python will not evaluate the remaining conditions, as the overall result will be
x = 10 y = 5 if x > 5 and y > 10: print("Both conditions are True")
In this example, the
if statement uses
and to check if both
x is greater than 5 and
y is greater than 10. However, since
x is 10 (which is not greater than 5), Python will not evaluate the second condition, as it already knows the overall result will be
Best Practices for Using
When using conditional statements, it’s essential to follow some best practices to write clean and maintainable code:
- Indentation: Ensure proper indentation for code blocks under
elifstatements to maintain readability.
- Use Parentheses for Complex Conditions: When you have complex conditions involving multiple logical operators, use parentheses to explicitly define the order of evaluation.
- Be Clear and Concise: Use meaningful variable names and comments to make your code easier to understand.
- Avoid Nested
ifStatements: While nesting
ifstatements can be useful, excessive nesting can make the code hard to read. Try to keep the nesting to a minimum.
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elif statements are powerful tools in Python that allow you to make decisions in your code based on specific conditions. By combining these if else and elif statements and following best practices, you can create flexible and efficient programs that respond to different scenarios appropriately. Now you may have got enough knowledge of if else and elif statement in python. If else are very important in python. so practice these examples and become a coding master. Happy Coding!