Python’s built-in delattr() function takes an object and an attribute name as arguments and removes the attribute from the object. The call delattr(object, ‘attribute’) is semantically identical to del object.attribute. This article shows you how to use Python’s built-in delattr() function. Usage Learn by example! Here’s an example on how to use the delattr() built-in … Read more
Static methods are special cases of class methods. They’re bound to a class rather than an instance, so they’re independent on any instance’s state. Python’s built-in function staticmethod() prefixes a method definition as an annotation @staticmethod. This annotation transforms a normal instance method into a static method. The difference between static (class) methods and instance … Read more
Python’s built-in function classmethod() prefixes a method definition in a class as an annotation @classmethod. This annotation transforms a normal instance method into a class method. The difference between class and instance method is that Python passes the class itself as a first implicit argument of the method rather than the instance on which it … Read more
In contrast to a normal Python method, an alias method accesses an original method via a different name—mostly for programming convenience. An example is the iterable method __next__() that can also be accessed with next(). You can define your own alias method by adding the statement a = b to your class definition. This creates … Read more
Challenge: Given is function f. How to assign the function to variable g, so that you can call g() and it runs function f()? Your desired output is function f‘s output: How to accomplish this in the most Pythonic way? Overview: We examine two methods to accomplish this challenge. You can run them in our … Read more
Many beginners who just start out with object-oriented programming in Python are confused about the purpose of the keyword “self”. Let’s resolve this confusion once and for all! The name self is, by convention, the name of the first argument of a Python class method. The variable self points to the concrete instance on which … Read more
Problem: If you assign a list object to a new variable using new_list = old_list, any modification to new_list changes old_list. What’s the reason for this and how can you clone or copy the list to prevent this problem? Example: Let’s consider the following example. Appending an element to the new_list also modifies the original … Read more
Do you hate those lengthy class definitions with __init__ and too many whitespaces and newlines? Python One-Liners to the rescue! Luckily, you can create classes in a single line—and it can even be Pythonic to do so! Sounds too good to be true? Let’s dive right into it! Problem: How to create a Python class … Read more
Summary: The key differences between raw_input() and input() functions are the following: raw_input() can be used only in Python 2.x and is obsolete in Python 3.x and above and has been renamed input() In Python 2.x, raw_input() returns a string whereas input() returns result of an evaluation. While in Python 3.x input() returns a string … Read more
You may know the following problem: You have an object’s attribute name as a string—say, you’ve read it from a file—and you want to access the attribute with the given name. But you cannot use the syntax object.”attribute” because the dot notation only allows for name-access like this: object.attribute. How do you resolve this problem? … Read more
Summary: To accept valid inputs from the user either use a While Loop With Custom Validations or use the PyInputPlus module to avoid tedious validation definitions. You can also use recursion to prompt the user for entering the valid input. Overview Problem: Given a user input; accept the input only if it is valid otherwise … Read more
Today, let’s discuss something that’s all over the place in many code bases: what does if __name__ == ‘__main__’ do in Python? The statement if __name__ == ‘__main__’: checks if variable __name__ is set to the string value ‘__main__’ which holds only within the main source file from which you initially execute your code. In all other … Read more