I am trying to learn using Dash by following those codes:
I am currently doing exercise 4. I wanted to change a dropdown menu for “Choose Borroughs:” from a multiple choice to a single choice. I changed dcc.Checklist into dcc.Dropdown and then lines 139-140 into:
and then line 220 into:
however after it, even though a dropdown menu looks like I wanted, the map disappears. I looked through the internet and can not find a solution for my issue.