Syntax and Definition The Python __contains__() magic method implements the membership operation, i.e., the in keyword. Semantically, the method returns True if the argument object exists in the sequence on which it is called, and False otherwise. For example, 3 in [1, 2, 3] returns True as defined by the list method [1, 2, 3].__contains__(3). … Read more
In which order does the nested ternary operator evaluate its conditions? Short Answer: The nested ternary operator ‘1’ if x else ‘2’ if y else ‘3’ evaluates the condition from left to right, i.e., ‘1’ if x else (‘2’ if y else ‘3’). In short, first condition first! Problem Formulation Given a nested ternary operator … Read more
Python es potente: puedes condensar muchos algoritmos en una sola línea de código. Así que surge la pregunta natural: ¿se puede escribir un bucle for en una sola línea de código? Este artículo explora con todo detalle esta cuestión fundamental. ¿Cómo escribir un bucle for en una sola línea de código Python? Hay dos formas … Read more
Showing pictures in Python This post will show different ways of displaying pictures in Python. The options we will explore are: PIL (Python Image Library) OpenCV (Computer Vision Library) IPython Matplotlib Library Method 1: PIL (Python Image Library) PIL is the standard library to manage images in Python. They discontinued the project in 2011, but … Read more
Syntax object.__call__(self[, args…]) The Python __call__ method makes a class callable, so you can call objects of the class like a normal function. For example, if you define __call__(self) on an object x of class X, you can call it like so: x(). The return value of the called object is the return value of … Read more
Syntax object.__repr__(self) The Python __repr__ method returns a string representation of the object on which it is called. It implements the built-in repr() function. If you call print(x) an object x, Python internally calls x.__str__() to determine the string representation of object x. If this isn’t implemented, Python calls x.__repr__(). We call this a “Dunder … Read more
The Pandas DataFrame has several methods concerning Computations and Descriptive Stats. When applied to a DataFrame, these methods evaluate the elements and return the results. Preparation Before any data manipulation can occur, two (2) new libraries will require installation. The Pandas library enables access to/from a DataFrame. The NumPy library supports multi-dimensional arrays and matrices … Read more
💡 Idea: Duck typing is a computer science concept where the type of an object is largely ignored—only the methods the object defines matter. This is sometimes referred to as dynamic typing because the type of an object is determined dynamically at runtime rather than checked by the compiler. Instead of checking the type, the … Read more
Abstract: You can easily add multiple values to a key in a Python dictionary using different methods. We’ll explain each of the possible methods in detail, and also show you how you can update and delete multiple values. Finally, we’ll show you how to add multiple values to a python dictionary by creating a function … Read more
Question Recap the following regular expression concepts (more details in the article below): The dot character . in regular expressions matches any character excluding the newline character. For example, the pattern ‘c.t’ will match the strings ‘cat’, ‘cut’, or ‘czt’. The character class [ ] is a set of characters: if you use it in … Read more
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
In the previous posts, we developed simple smart contracts, deployed them using Remix or Truffle, and interacted with them using JSON-RPC interface providers such as using web3.py or web3.js. In this post, we shall take a closer examination into how a smart contract works on the Ethereum blockchain at the grass root. More precisely, we … Read more