The three most common open source technologies for writing data science programs are Python, SciLab, and R. Here's how to write program-defined functions in R. There's no clear definition of the term ...

Learn how to use XPath functions and operators to select and extract data from web pages. This article covers some of the most common and useful XPath expressions for web scraping.

M4N asks:. Is there a reason why functions in most(?) programming languages are designed to support any number of input parameters but only one return value?