Python’s conditional statements allow you to execute different blocks of code based on certain conditions. The most common conditional statements in Python are if, elif (else if), and else. Here’s a detailed look at how to use these statements with various examples.
Basic if Statement
The if statement is used to execute a block of code only if a specified condition is true.
Example:
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x = 10 if x > 5: print("x is greater than 5") |
The else Statement
The else statement can follow an if statement and is executed if the if condition is false.
Example:
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age = 17 if age >= 18: print("You are an adult.") else: print("You are a minor.") |
The elif Statement
The elif (else if) statement allows you to check multiple conditions after the initial if condition. If the if condition is false, it checks the elif conditions in order.
Example:
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score = 75 if score >= 90: print("Grade: A") elif score >= 80: print("Grade: B") elif score >= 70: print("Grade: C") else: print("Grade: F") |
Nested if Statements
You can nest if statements within other if statements to check for further conditions.
Example:
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num = 15 if num >= 10: print("Above ten,") if num > 20: print("and also above 20!") else: print("but not above 20.") |
Short Hand if
If you have only one statement to execute, you can put it on the same line as the if statement.
Example:
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if x > 5: print("x is greater than 5") |
Short Hand if-else
This form, known as a ternary operator, allows you to execute a single statement for each of the true and false conditions of the if.
Example:
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message = "Adult" if age >= 18 else "Minor" print(message) |
Combining Logical Operators
Use logical operators (and, or, not) to combine conditional statements.
Example:
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x = 25 if x > 10 and x < 30: print("x is greater than 10 and less than 30") if not(x < 10 or x > 30): print("x is between 10 and 30") |
The pass Statement
if statements cannot be empty, but if you for some reason have an if statement with no content, use the pass statement to avoid an error.
Example:
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if x > 5: pass |
Understanding and effectively using conditional statements are crucial in Python programming. They allow you to control the flow of your program and make decisions, thereby making your programs more dynamic and responsive to different inputs or situations.