Hello All,
Great work on Streamlit, guys. Thanks!
I have a question, which really gave me a headache; however, it might (and hope) be simpler than it seems. So, I want to have a dashboard with 4 dropdown lists and the dropdown values should be dependent on the value that the user selects on the other dropdown lists. Think of the following example: If I have a dropdown list of countries and another of cities… If I select “the Netherlands” in the first dropdown list, I would only like to see cities of the Netherlands in the second dropdown list. I would also like to do it the other way around. I would like to be able to choose “Amsterdam” in the second dropdown list and then when I go to the first dropdown list I should only see “the Netherlands” (I should not be able to pick any other country if I have chosen “Amsterdam” in the second one.)
When this is with 2 dropdown lists, it could be possible to write an extensive code with lots of “if” but when I have 4 dropdown lists this way would be give a super long code 
I hope my explanation is clear and I will be really happy to hear that I can do that with Streamlit because I want to keep using it since it is super handy 
Thank you in advance!