In this short blog post, I tackle an error related to a classic problem within machine learning: how to treat unseen categorical values and solve the “found unknown categories” error. Imagine you have a train and a test data set with the following values in a column: Train: [‘green’, ‘red’,…
In the past couple of weeks, I started to use sklearn pipelines more intensively. It seemed like a good project to find out more about them and share my experiences in a blog post. So here it is: a sklearn pipeline tutorial. Why pipelines? In most machine learning projects, you…
When you have a scatter plot in Tableau, you often want to add a trend line to indicate a relationship between two variables. However, sometimes it appears that it’s impossible: it’s greyed out and there is a tooltip that says “trend lines are not supported when marks are stacked”. Let’s…
In this blog post, you will learn to remove URL parameters from a column that contains page path URLs. We do this by using the REGEXP_REPLACE function that is available in Tableau. What are URL Parameters? Url Parameters or query strings are added in the back of we web address.…
In a previous post, I explained how you can sample two Pandas DataFrame exactly the same way. In this blog post, I want to use that helper function to undersample your predictors and target variable. When you are working with an imbalanced data set, it’s often good practice to under-…
I’ve been trying to build a model using machine learning today and I bumped into an error when I wanted to dummify my categorical predictors. It seemed I didn’t really know how Scikit’s OneHotEncoder worked. But I do now. And I want to share it with you. I had a…
Google Spreadsheets and R: a dynamic duo! An annoying feature in googlesheets4’s read_sheet(), is that within a column, it assigns a type to each cell individually when it is confused. However, this makes perfect sense. Sometimes, a column contains a mix of values that could be integers and values that…
In this blog post, two quick solutions to sample two pandas data frames in the same way. Why? Because sometimes you load your predictors (X) and your target (y) from two different files and you don’t want to put them together in one table. Sampling two data frames with a…
Warning: this blog post touches on a rather technical subject and is not aimed towards beginners. If you ever built a web scraping script, in R, or any other programming languagen, you know how long it can take to scrape a sizeable amount of web pages. The same goes for…
When I exported my CSV in R, its values were split on a semicolon. I, a Tableau rookie, wanted to import that file. I’ve bumped into several BI tools that didn’t have an options to specify a custom separator, but for a robust tool like Tableau, that seemed unbelievable. Depending…