Bot Composer - Join list from Luis entity

Question

Bot Framework Composer v1.4.1

I have a bot connected to Luis, which returns a list entity that I need to operate with that data. The entity that I get is a list of categories, and I need to concatenate all the elements of that list into a string

"entities": {
  "CategoryList": [
    [
      "sub-13-Imprimante",
      "12-materiels"
    ]
  ]
}

The expected result is

"sub-13-Imprimante,12-materiels"

I have tried different options but none concatenate the result as expected.

@CategoryList //This only assign first element of the array ("sub-13-Imprimante")

join(@CategoryList, ',') //Throw error

The error obtained in the join statement is:

System.InvalidOperationException: 'NewTicket.fr-fr.lg:@CategoryList evaluates to sub-13-Imprimante which is not a list. [SendActivity_D8EXfc]  Error occurred when evaluating '- ${join(@CategoryList, ',')}'. 

It would seem that when calling @CategoryList, it already returns the first item, instead of the entire list.

How could I do to obtain all the values of the array concatenated in a string?

Answer 1

@CategoryList will return the first and only the first value found for the entity. @@CategoryList will return the entire thing. So, what you need is join(@@CategoryList, ',')

See more info here:

https://learn.microsoft.com/en-us/composer/concept-memory?tabs=v2x#memory-shorthand-notations