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Robert Vásquez
Robert Vásquez

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Functional programming with python

Introduction to the Functional Programming Paradigm

The functional programming paradigm is an approach that focuses on the use of functions as fundamental elements in the design and development of programs. Unlike other paradigms, such as imperative or object-oriented programming, the functional paradigm is based on the idea that programs should be primarily composed of pure functions, which are functions that have no side effects and always produce the same result for the same input data.

Characteristics of the Functional Programming Paradigm

  • Pure Functions: Pure functions are the fundamental building blocks of functional programming. These functions do not modify global state or have side effects, which facilitates understanding and reasoning about the code.

  • Immutability: In the functional paradigm, data is immutable, which means it cannot be modified once created. Instead of making changes to existing data, new data structures are created with the results of operations.

  • Lazy Evaluation: In functional programming, expressions are lazily evaluated, meaning they are evaluated only when needed. This allows for performance optimization and avoids unnecessary execution of code.

Examples of Functional Programming in Python

Here are some examples of applying the functional programming paradigm in the Python language:

  1. Functions as First-Class Citizens: In Python, functions are first-class citizens, which means they can be assigned to variables, passed as arguments, and returned as results from other functions. This enables function composition and the development of more modular programs.

Example:

def apply_function(function, value):
    return function(value)

def double(number):
    return number * 2

result = apply_function(double, 5)
print(result)  # Output: 10
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  1. Use of Higher-Order Functions: Higher-order functions are those that can take functions as arguments or return functions as results. This facilitates the creation of abstractions and the development of generic operations that can be applied to different data sets.

Example:

def apply_operation(operation, list):
    return [operation(element) for element in list]

def square(number):
    return number ** 2

numbers = [1, 2, 3, 4, 5]
result = apply_operation(square, numbers)
print(result)  # Output: [1, 4, 9, 16, 25]
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  1. Use of Lambda Functions: In Python, lambda functions are anonymous functions with a single expression. These functions are useful when a simple function is needed and it's not necessary to define it separately.

Example:

numbers = [1, 2, 3, 4, 5]
result = list(map(lambda x: x ** 2, numbers))
print(result)  # Output: [1, 4, 9, 16, 25]
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Conclusion

The functional programming paradigm offers a different approach to software development, focusing on the composition of pure functions and the treatment of data as immutable. Python, as a flexible programming language, allows for the implementation of functional programming concepts and techniques, making it easier to develop more concise and readable programs.

It's important to note that this summary is only an introduction to the functional programming paradigm with examples in Python. For a more comprehensive understanding, it is recommended to explore additional resources and practice the concepts presented.

I hope this information is helpful and aids in your understanding of the functional programming paradigm and its application in Python.

Top comments (1)

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Woojin Jang

Thank you for your information about functional programming.
By the way, as a non-native English user, what is the meaning of "first-class citizen" or "higher-order function"? Are there "second-class citizen" or "lower-order function"? If then, could you explain these terms?
Thank you.