Python Booleans

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Python Booleans

In Python, Booleans are a fundamental data type used to represent logical values.

A Boolean can hold only two possible values:

    • True

    • False

Booleans play a crucial role in decision-making, comparisons, and control flow.

Boolean Expressions

Any expression in Python that involves comparison or logic evaluates to either True or False.

Example: Comparing Values

print(5 > 3) print(7 == 10) print(4 <= 4)

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Python evaluates each expression and returns a Boolean result.

Booleans in Conditional Statements

Booleans are commonly used in if-else statements to control program execution.

Example: Conditional Logic

marks = 72 passing_marks = 50 if marks >= passing_marks: print("Student passed the exam") else: print("Student failed the exam")

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Here, Python checks the condition and executes code based on whether it is True or False.

Evaluating Values with bool()

The bool() function allows you to test any value and determine its Boolean truth value.

Example: Evaluating Direct Values

print(bool("Python")) print(bool(0)) Example: Evaluating Variables language = "Java" version = 0 print(bool(language)) print(bool(version))

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Truthy Values in Python

Most values in Python evaluate to True when converted to Boolean.

Examples of truthy values:

    • Non-empty strings

    • Non-zero numbers

    • Non-empty collections (lists, tuples, sets, dictionaries)

Example

print(bool("Code")) print(bool(99)) print(bool({"name": "Alex"}))

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Falsy Values in Python

Only a limited set of values evaluate to False.

Examples of falsy values:

    • False

    • None

    • 0

    • Empty strings

    • Empty collections

Example

print(bool("")) print(bool([])) print(bool(None)) print(bool(0))

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Custom Objects and Boolean Evaluation

An object can also evaluate to False if its class defines a __len__() method that returns 0.

Example

class Cart: def __len__(self): return 0 my_cart = Cart() print(bool(my_cart))

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Even though the object exists, Python treats it as False.

Functions Returning Boolean Values

Functions can return Boolean results and be used directly in conditions.

Example: Boolean Function

def is_logged_in(): return False print(is_logged_in())

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Example: Using Function in Condition

def has_access(): return True if has_access(): print("Access granted") else: print("Access denied")

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Built-in Functions That Return Booleans

Python provides many built-in functions that return Boolean values.

One commonly used function is isinstance().

Example: Type Checking

value = 3.14 print(isinstance(value, float))

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This helps validate data types during runtime.

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