It’s been a couple of years since I first used NetworkX in Python. Something that I expected to be truly obvious was adding node attributes to your network, preferably when calling a from_pandas_… function. However, that wasn’t the case. In this article, we’ll create a network from an edge list…
Today, I tried a data transformation that seemed so obvious: splitting the string values of a Pandas column on a delimiter and one-hot encode the resulting strings. However, it took me quite some time to figure out how to do it elegantly. Here’s what I wanted to achieve. I had…
I ran into another silly error, for which I wanted to share the solution in order to save you some time. It occurs when trying to run a query using Python’s SQLAlchemy libary. Let’s dive right in. The problem When you’re trying to run a query, either by using Pandas’…
In this blog post, we’ll make a treemap in Python using Plotly Express. While this seems like a trivial task, there are some intricacies involved. I ran into multiple error, and I want to make sure you don’t. First, let’s load all relevant packages that you’re gonna need throughout this…
Recently, I needed to calculate the relative change of a value compared to the first value within a DataFrame group, a GroupBy object. With SQL, I would use a window function (e.g. PARTITION BY in PostgreSQL). In this article, we’ll do it in Pandas (Python). To demonstrate, let’s start with…
In this blog post, I explore the options for taking the row-wise sum of a subset of columns from a Pandas DataFrame. Let’s try to take the row-wise sum of the columns first_column, second_column, and third_column. This means we’re leaving other_column out. But first, let’s take a step back. If…
In this blog post we’ll do a small thing to remove trailing or leading whitespaces from a DataFrame’s column names. This is something that can occur when working with files that haven’t been properly formatted. There are multiple things you can do to fix this. First, let’s create some dummy…
Because there are (too) many ways to cast a Pandas DataFrame from long to wide format, I decided to list four ways to achieve that goal. The four functions I describe in this article are the following. Function Object aggregation Can handle NaNs pivot DataFrame no no pivot_table DataFrame yes…
In this article we elaborate on the multiple ways to remove the final line of a CSV in Python when loading it with Pandas’ read_csv function. Remove final row(s) after loading the file Removing the final row from a Pandas DataFrame can be done with a simple slice. The following…
There are very few occasions when you really need a hierarchical column index in Pandas. Mostly, you just want to identify a column with a single column name. In this blog post, we’ll learn how to properly flatten a DataFrame with MultiIndex columns. One of the things that annoys me…