Dependent Dropdowns

Hi! Does anyone know how to make one dropdown element depend on another? I have a list of 130 engines that are categorized by 4 regions. I want the first dropdown to be the region and the second dropdown to fill the specific engines for that region.

I’m new to Dash but have been working with Flask. I got it to work in Flask but using JavaScript. Not sure if that translates into Dash well.

Let me know if that makes sense and if you have any ideas! Thanks!

hi @bpolasek

:wave: Welcome to the community.

That is what we call a chained callback.

You can find a few more examples in the Dash Example Index, under the callbacks → chained section


Okay thanks! I will have to check it out!

Hi @bpolasek, in addition to @adamschroeder’s example here is another one:


Thank you!!