Python’s built-in type() function has two purposes. First, you can pass an object as an argument to check the type of this object. Second, you can pass three arguments—name, bases, and dict—to create a new type object that can be used to create instances of this new type. Usage Learn by example! Here’s an example … Read more
Python’s built-in object() function takes no argument and returns a new featureless object—the base and parent of all classes. As such it provides all methods that are common to all Python class instances such as __repr__() and other “dunder” methods. However, unlike for all non-object instances, you cannot assign arbitrary attributes to an instance of … Read more
Python’s built-in repr(obj) function returns the standard string representation of the provided object. This often includes the type and memory address of the object—for lack of further information. For example, the returned string representation may be ‘<main.Car object at 0x000001F66D11DBE0>’ for a custom object of type Car. The function internally calls the method obj.__repr__() which … Read more
Python’s built-in str(x) function converts the object x to a string using the x.__str__() method or, if non-existent, the repr(x) built-in function to obtain the string conversion. Syntax str() Syntax: str(object) # –> Most common case: convert an object to a string str(object=b”, encoding=’utf-8′, errors=’strict’) # –> Not so common case: Converts a bytes or … Read more
Python’s built-in issubclass(X, Y) function takes a class X and a class Y and returns True if the X is an instance of Y and otherwise False. The argument Y can also be a tuple in which case it checks whether X is a subclass of any class in the tuple—such as in issubclass(X, (class_1, … Read more
Python’s built-in isinstance(object, class) function takes an object and a class as input arguments. It returns True if the object is an instance of the class. Otherwise, it returns False. Instead of a class, you can also pass a tuple of classes to check if the object is an instance of any of the classes … Read more
Problem: What is the best way to check whether a given object is of a given type? For example, if you have a variable object, how to check if it’s a string? Check with Subclasses Solution: To check if an object is an instance of str or any of its subclasses, use isinstance: Note that … Read more
Hello fellow Finxters! I am back with another installment of top 10 cheat sheets. This time, we will be compiling a list of Python Object Oriented Programming (OOP) cheat sheets to make it easier to write programs to keep on hand! Let us dig right in without wasting any more time! Here’s the cheat sheet … Read more
Python’s built-in “dunder” function __import__() allows you to import a library by name. For example, you may want to import a library that was provided as a user input, so you may only have the string name of the library. For example, to import the NumPy library dynamically, you could run __import__(‘numpy’). In this tutorial, … Read more
As a programmer, you generally appreciate more control of your data and more control on the behavior of my program itself. It is in this moment when Python comes in our help with all its power letting us get right into the flow of our programming, avoiding us to lose something like define an attribute … Read more
Python’s built-in getattr(object, string) function returns the value of the object‘s attribute with name string. If this doesn’t exist, it returns the value provided as an optional third default argument. If that doesn’t exist either, it raises an AttributeError. An example is getattr(porsche, ‘speed’) which is equivalent to porsche.speed. Usage Learn by example! Here’s an … Read more
Python’s built-in setattr(object, string, value) function takes three arguments: an object, a string, and an arbitrary value. It sets the attribute given by the string on the object to the specified value. After calling the function, there’s a new or updated attribute at the given instance, named and valued as provided in the arguments. For … Read more