Curious about the usage of the various "internal" (built-in, not user defined) functions in use is a wide range of PHP applications, Joshua Thijssen did some research on GitHub and has shared the results on his site today.
How many internal PHP functions (things like count(), strpos(), array_merge() etc), does PHP have? Depending on which version you use, and how many extensions you have loaded, somewhere between 1000 and 2000 would be a good guess. But how many of these internal functions are you REALLY using?
He created a custom script to fetch the results of a custom query (one that found repos with over fifty stars), grabbed the source and parsed the results looking for these internal functions. He shares the results of his parsing from 967 repos in the remainder of the post, including: the top ten most called, some interesting facts found in the results and some of the "bad" ones in wide use (like "exec" and "mysql_connect").