Mathematica has a number of functions to test if expressions represent a type of object. A summary is provided in the Help section guide/TestingExpressions. Unfortunately, there does not seem to be a "URLQ" to test if an expression is a string containing an URL. I could probably come up with some sloppy heuristics to write my own, but I was wondering if there was a best practice for testing if an expression contains a URL. Please let me know if you have any suggestions.
