Function Interfaces in Python

 

10. Combining Concepts

def trace(func):

    

    """A decorator that traces function calls."""

    

    def wrapper(*args, **kwargs):

        print(f"TRACE: calling {func.__name__}() with {args}, {kwargs}")

        result = func(*args, **kwargs)

        print(f"TRACE: {func.__name__}() returned {result}")

        return result

    return wrapper

@trace

def compute_area(length: float, width: float) -> float:

    """Compute the area of a rectangle."""

    return length * width

area = compute_area(3.0, 4.5)

# clcoding.com

TRACE: calling compute_area() with (3.0, 4.5), {}

TRACE: compute_area() returned 13.5

9. Decorators

def debug(func):

    """A decorator that prints the function 

    signature and return value."""

    def wrapper(*args, **kwargs):

        print(f"Calling {func.__name__} with {args} and {kwargs}")

        result = func(*args, **kwargs)

        print(f"{func.__name__} returned {result}")

        return result

    return wrapper

@debug

def add(a, b):

    """Add two numbers."""

    return a + b

add(3, 4)

# clcoding.com

Calling add with (3, 4) and {}

add returned 7

7

8. Lambda Functions

square = lambda x: x * x

print(square(5))  

# clcoding.com

25

7. First-Class Functions

def square(x):

    """Return the square of x."""

    return x * x

def apply_function(func, value):

    """Apply a function to a value 

    and return the result."""

    return func(value)

result = apply_function(square, 4)

print(result)  

# clcoding.com

16

6. Docstrings

def divide(x, y):

    """

    Divide x by y and return the result.

    

    :param x: numerator

    :param y: denominator

    :return: division result

    """

    return x / y

result = divide(10, 2)

print(result)  

# clcoding.com

5.0

5. Function Annotations

def multiply(x: int, y: int) -> int:

    

    """Multiply two integers 

    and return the result."""

    

    return x * y

result = multiply(3, 4)

print(result)

# clcoding.com

12

4. Arbitrary Keyword Parameters

def print_info(**kwargs):

    

    """Print key-value pairs 

    from keyword arguments."""

    

    for key, value in kwargs.items():

        print(f"{key}: {value}")

print_info(name="Clcoding", age=30, city="Earth")

# clcoding.com

name: Clcoding

age: 30

city: Earth

3. Arbitrary Positional Parameters

def sum_all(*args):

    

    """Sum all given arguments."""

    

    return sum(args)

total = sum_all(1, 2, 3, 4, 5)

print(total)  

# clcoding.com

15

2. Keyword Parameters

def greet(name, greeting="Hello"):

    """Greet someone with a provided 

    greeting or a default greeting."""

    return f"{greeting}, {name}!"

message = greet("Clcoding")

print(message)  

message = greet("Python", "Hi")

print(message) 

# clcoding.com

Hello, Clcoding!

Hi, Python!

1. Basic Function Definition

def add(a, b):

    

    """Add two numbers and 

    return the result."""

    

    return a + b

result = add(3, 5)

print(result)  

# clcoding.com

8