Variable Type Gotchas - ColdFusion Lists and Empty Elements

As a follow up to my earlier post, another common ‘gotcha’ with ColdFusion Lists are empty list items. What’s an empty list item? Consider this simple list of names:

<cfset names="Baltar,Apollo,Starbuck,,Bozo">

I think most people, including myself, would look at that and say that the list had 5 items, with the 4th item being a simple empty string. But ColdFusion simply ignores empty list items. If you perform a listLen() on that string, you get 4.

Now - we can argue about whether or not that makes sense. I’m not quite sure it does - but that’s how ColdFusion handles it. If you want to handle this differently, you need to write your own code, or perhaps replace the empty items with a string that will represent ‘null’ for your application. Check out ListFix() at CFLib.org for a UDF that does this.

Thanks to Phillip Senn for reminding me of this - I actually forgot it during my presentation.

More Variable Type Gotchas tomorrow - after I arrive at cf.Objective!

Raymond Camden's Picture

About Raymond Camden

Raymond is a developer advocate. He focuses on JavaScript, serverless and enterprise cat demos. If you like this article, please consider visiting my Amazon Wishlist or donating via PayPal to show your support. You can even buy me a coffee!

Lafayette, LA https://www.raymondcamden.com

Comments