Sélect item list error

after i click on a button i request the value in the cloudDB "account" tag
the following blocks are represented in the attached image.
an error is notified to me at the level of the block select element in the list. the error is: "The operation select list item cannot accept the arguments:, [" admin "], [1]
I would like to know why while I have structured the data well.
in the tag we have items each of which is a list that represents an account.

No image attached, please post your blocks

the picture is attached

From your blocks, it appears you are testing if a username exists before adding a new user to the list. I find it easier to extract all the usernames, then test that local list against the textbox.

Try something like this:

I tried the code but it still shows me the error message related to the choose list element block
yet each element in the value of the tag is a list
the error message is: <The operation select list item cannot accept the arguments: < The operation select list item cannot accept the arguments: , ["admin"], [1] >

Set your value of tag compte to a label to see what you have in your list

with a button i reset the ta then fill it as the picture shows. then I click on the account creation button
then as you ask i display it on a label and the result is:
["admin", "admin", 1, "alimi"]

I suggest you look at the blocks in my .gotValue again and make sure you have copied these correctly.

You expect tag compte to contain a value that is a list of lists (a 2 dimensional list, or a table).

But your first storeValue action sets its value to a one dimensional list.

Wrap that make-a-list block with a second make-a-list to turn it into a two dimensional list, with the first item being the admin list.

As ABG says only use the "Append to List" block, not the "StoreValue" block

StoreValue makes ["admin","admin","1","alimi"]

Append to List makes [["admin","admin","1","alimi"]]

select item from list will give you the sublist

If you use Append to List for all new values, you will need an empty list there in the DB first, right?

yes I will need an empty list first. But I can take care of it
I think I understand the concept better and better. As for adding an account, I was able to solve the problem as you explained. On the side of reading the data it is not yet clear but it is coming.

In short, the block must create an empty list to be able to consider the content of a tag as a list

Sort of. You are appending a list to a list, so you must have a list to append to. Example structure after appending a second user:


in your tag you now have a list of lists, the outer list, and two items for that list, each of which is a list.

Yes I noticed that thank you very much for your help