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Software Development Wolfram Language

Test if expression is a URL - URLQ?

Posted 8 years ago

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.

POSTED BY: Donald Pellegrino

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Posted 8 years ago

There is a regex to test whether a string represents a correct URL according to RFC 3986, which is a part of commercial RegexBuddy Library. It is quite complicated though, so if you don't need a strong verification you can use one of the solutions from the following SO thread: What is the best regular expression to check if a string is a valid URL?

POSTED BY: Alexey Popkov

Posted 8 years ago

The problem is that what can be considered a URL actually varies depending on context. And sometimes something that is not a complete URL can be promoted to one. I suggest you look up `Interpreter["URL"]` and its restrictions. Then you'll probably be able to write something like: URLQ[s_] := !FailureQ[Interpreter["URL"][s]]

POSTED BY: Carlo Barbieri

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