On the SitePoint PHP blog they've posted a new tutorial showing you how to analyze tweet sentiments using a combination of PHP and machine learning (with the help of the php-ai/php-ml library).

As of late, it seems everyone and their proverbial grandma is talking about Machine Learning. [...] Yes, what about Machine Learning and PHP? Fortunately, someone was crazy enough not only to ask that question, but to also develop a generic machine learning library that we can use in our next project. In this post we are going take a look at PHP-ML – a machine learning library for PHP – and we’ll write a sentiment analysis class that we can later reuse for our own chat or tweet bot.

The post then starts in with some of the basics of machine learning and sentiment analysis and briefly introduces the php-ml library and what functionality it offers. It then outlines the problem they're trying to solve and the solution including what data points php-ml will use to determine the sentiment of a tweet. The author shows how to get the php-ml package installed, how to read in the data set and how to "exercise" the sentiment analysis against the tweets. It describes how the evaluation works and shows the accuracy result of a basic run.