Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.Simple if/else Expressions | Conditional Statements
Introduction to Python
course content

Course Content

Introduction to Python

Introduction to Python

1. First Acquaintance
The Very First StepsCommentsSome Simple MathMore Challenging MathChallengeBringing It All Together
2. Variables and Types
Storing NumbersNaming RulesUsing VariablesData TypesNumbersChallengeStoring TextString IndexingNegative Indexing and LengthString SlicingChallengeConcatenation
3. Conditional Statements
Boolean Data TypeChallenge: Comparison OperatorsCombining ConditionsChallenge: Logical OperatorsMembership Operators and Types ComparisonSimple if/else ExpressionsChallenge: Grocery StoreChallenge: Odd and Evenif/elif/else ExpressionsChallenge: Grocery Store ExtendedChallenge: Positive, Negative or Zero
4. Other Data Types
What Is a List?List MethodsChallengeNested ListsChallengeWhat Is a Tuple?Tuple MethodsChallengeNested TuplesChallengeWhat Is a Dictionary?ChallengeDictionary MethodsChallenge
5. Loops
while LoopChallengefor LoopChallengeRangeChallengeIterating Over IndexesNested Loops
6. Functions
Built-in FunctionsChallengeDefining Your First FunctionChallengeif/else Statements in FunctionsChallengeFunctions With No ReturnChallengeModifying FunctionsChallengeLambda FunctionsChallenge

bookSimple if/else Expressions

Now that we're acquainted with conditional operators and know how to use them, we can branch our code based on certain conditions. In Python, this is achieved with the following structure:

In the example above, the condition can be either a conditional statement or a boolean value. For example, it might look like a != 4 or b > 100. The commands beneath if and else are instructions to be executed depending on whether the condition is met. These could be print() functions, variable assignments, arithmetic operations, string manipulations, and more.

Let's walk through an example: Suppose you have a string and you want to determine if it's long. We'll define a string as 'long' if it contains more than 20 characters.


              
1234567891011121314151617

            
# Assign some variable
test = "small string"

# Conditional statement
if len(test) > 20:
    print("This string is long!")
else:
    print("Nothing special")
    
# Check on different string
test = "This string is very-very and very large"

# Conditional statement
if len(test) > 20:
    print("This string is long!")
else:
    print("Nothing special")
copy

Note

Remember, the code blocks under the if and else statements should have consistent indentation (e.g., 2 spaces, 4 spaces, etc.).

Given the provided `if/else` block, what will be the output if `a = 95`, and what if `a = 56`?

Given the provided if/else block, what will be the output if a = 95, and what if a = 56?

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 3. Chapter 6
some-alt