Sometimes you want to dynamically generate a custom dropdown in your application. It could be using the values from a dataset column or using the six last month's values from today.
You can actually do this using the "edit project variable" tile of a Dataiku application.
Click on "Use custom UI" below the input for auto-generated controls, you'll see you have an input to add a python code.
The python function should look like this:
def do(payload, config, plugin_config, inputs):
choices = [
{ "value" : "val1", "label" : "Value 1"},
{ "value" : "val2", "label" : "Value 2"}
]
return {"choices": choices}
Note: If you load a dataset from it, don't forget to mention the project key as each app instance has its own project key.
Then in the auto-generated controls, you must specify the choices has been generated from the python:
[
{
"type": "SELECT",
"name": "variable_name",
"getChoicesFromPython": true
}
]
You can use SELECT or MULTISELECT for the types.
Check these screenshots to see an example where I wanted to update a project variable to filter a dataset according to one of the country codes available in the input dataset.

Fig 1: You use a filter recipe, filtering on columns using a project variable value.

Fig 2: Use the custom UI in Edit project variable tile of a Dataiku App to write the python do function.

Fig 3: That’s it you have made an App where the dropdown to select the country is generated from a dataset.