Chris

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.To help students reach higher levels of Python success, he founded the programming education website Finxter.com that has taught exponential skills to millions of coders worldwide. He's the author of the best-selling programming books Python One-Liners (NoStarch 2020), The Art of Clean Code (NoStarch 2022), and The Book of Dash (NoStarch 2022). Chris also coauthored the Coffee Break Python series of self-published books. He's a computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.

Python __dir__() Magic Method

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Python’s __dir__() magic method implements the functionality of the dir() built-in function. Semantically, dir() returns all (function, object, or variable) names in a given scope. However, the magic method __dir__() converts any return value to a sorted list. Minimal Example The following code defines a custom class My_Class and overrides the __dir__() magic method to … Read more

The Shortest Quicksort Algorithm in Python

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Quicksort is not only a popular question in many code interviews – asked by Google, Facebook, and Amazon – but also a practical sorting algorithm that is fast, concise, and readable. Because of its beauty, you won’t find many introductions to algorithms that don’t discuss the Quicksort algorithm. In this one-liner tutorial, you’ll learn about … Read more

Python __trunc__() Magic Method

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Syntax and Definition object.__trunc__(self) The Python __trunc__() method implements the behavior of the math.trunc() function. For example, if you attempt to call math.trunc(x), Python will run the x.__trunc__() method to obtain the return value. We call this a “Dunder Method” for “Double Underscore Method” (also called “magic method”). To get a list of all dunder … Read more

Python __floor__() Magic Method

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Syntax and Definition object.__floor__(self) The Python __floor__() method implements the behavior of the math.floor() function. For example, if you attempt to call math.floor(x), Python will run the x.__floor__() method to obtain the return value. We call this a “Dunder Method” for “Double Underscore Method” (also called “magic method”). To get a list of all dunder … Read more

Python __ceil__() Magic Method

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Syntax and Description object.__ceil__(self) The Python __ceil__() method implements the behavior of the math.ceil() function. For example, if you attempt to call math.ceil(x), Python will run the x.__ceil__() method to obtain the return value. We call this a “Dunder Method” for “Double Underscore Method” (also called “magic method”). To get a list of all dunder … Read more

Python __round__() Magic Method

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Syntax object.__round__(self, ndigits=0) The Python __round__() method implements the built-in round() function. For example, if you attempt to call round(x) or round(x, ndigits), Python will run the x.__round__() or x.__round__(ndigits) method, respectively. The following code snippet overrides the __round__() dunder method to return the rounded age of a Person when you pass an object of … Read more

Python __rdiv__ Magic Method

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The Python __rdiv__() magic method overrides the reverse division operation for a custom object in Python 2. In Python 3, it was replaced by the __rtruediv__() and __rfloordiv__() dunder methods. The Python __rtruediv__() method is called to implement the normal division operation / called true division and apply it in reverse. The Python __rfloordiv__() method … Read more

Python __neg__ Magic Method

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To customize the behavior of the negation operator -x, override the __neg__(self) dunder method in your class definition. Python internally calls x.__neg__() to calculate the inverse (negation) of an object, i.e., -x. If the __neg__() method is not defined, Python will raise a TypeError. Syntax __neg__(self) To use the negation operator -x on a custom … Read more

How to Override the “not” Operator in a Python Magic Method?

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Short Answer: To override the logical not operator for a custom Python class My_Class, redefine the dunder method My_Class.__bool__() to return your custom Boolean value. This ensures that bool(x) on a My_Class object x returns either True or False. The operation not x will then return the inverse Boolean value, i.e, not x evaluates to … Read more

Python __iter__() Magic Method

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Syntax object.__iter__(self) The Python __iter__ method returns an iterator object. An iterator object is an object that implements the __next__() dunder method that returns the next element of the iterable object and raises a StopIteration error if the iteration is done. Formally, the __iter__() method implements the built-in iter() function. For example, if you call … Read more