How to Initialize a NumPy Array? 6 Easy Ways

Problem Formulation and Solution Overview In this article, you’ll learn how to initialize a NumPy array in Python using six (6) of the most commonly used methods. Background: NumPy is Python’s impressive array-based data structure library used to perform intense mathematical calculations popularized by the Machine Learning and Data Science community. Let’s start by creating … Read more

np.argsort() — A Simpe Illustrated Guide

In Python, the numpy.argsort() function returns the indices that would sort an array in ascending order.  Here is the argument table of the numpy.argsort() function. If it sounds great to you, please continue reading, and you will fully understand the numpy.argsort() function through Python code snippets and vivid visualization. This tutorial is about numpy.argsort() function.  … Read more

np.gradient() — A Simple Illustrated Guide

In Python, the numpy.gradient() function approximates the gradient of an N-dimensional array. It uses the second-order accurate central differences in the interior points and either first or second-order accurate one-sided differences at the boundaries for gradient approximation. The returned gradient hence has the same shape as the input array.  Here is the argument table of … Read more

Normal Distribution and Shapiro-Wilk Test in Python

Normal distribution is a statistical prerequisite for parametric tests like Pearson’s correlation, t-tests, and regression. Testing for normal distribution can be done visually with sns.displot(x, kde=true). The Shapiro-Wilk test for normality can be done quickest with pingouin‘s pg.normality(x). 💡 Note: Several publications note that normal distribution is the least important prerequisite for parametric tests and … Read more

Pearson Correlation in Python

A good solution to calculate Pearson’s r and the p-value, to report the significance of the correlation, in Python is scipy.stats.pearsonr(x, y). A nice overview of the results delivers pingouin’s pg.corr(x, y).  What is Pearson’s “r” Measure? A statistical correlation with Pearson’s r measures the linear relationship between two numerical variables. The correlation coefficient r … Read more

How to Remove Specific Elements in a Numpy Array

Summary: The most straightforward way to remove an element at a given index from a NumPy array is to call the function np.delete(array, index) that returns a new array with the element removed. Problem: Given a Numpy Array; how to remove specific elements from the Numpy array? Example: Consider the following Numpy array as shown below: Challenge: How will you … Read more

How to Calculate z-scores in Python?

The z-scores can be used to compare data with different measurements and for normalization of data for machine learning algorithms and comparisons. 💡 Note: There are different methods to calculate the z-score. The quickest and easiest one is: scipy.stats.zscore(). What is the z-score? The z-score is used for normalization or standardization to make differently scaled … Read more