how to get a list with the value of the positions that contain a value.

[Adolfo_Enrique_]

Hello everyone, I need help to solve the following.

From a list with n data, how to get a list with the value of the positions that contain a value.

For example, from the following List( Pear,banana,Apple), the result I need to obtain is LIST(1,2,3)

Gracias!

[TeeSee1]

One way you could do this is (I haven't tried it, but should work😅)

1. Create a read only table (ie Lists) like

   ID	ELEMENTS
   1	1
   2	1,2
   n max number of your list size	1,2,3,,,,n

2. An expression:

SPLIT(
 LOOKUP(
  COUNT([Your LIST HERE]),
  "Lists",
  "ID",
  "ELEMENTS"
 ),
 ","
)

If you need a very long list, you can write actions to create such lists but probably it will take a long time to execute and not fit your use case, whatever that may be.

[TeeSee1]

@Suvrutt_Gurjar  briefly submitted and deleted a post which I believe could be quite relevant. 

So, @Adolfo_Enrique_ , if you are looking for functionality of INDEXOF(), which AppSheet does not provide natively, you should do a search on INDEXOF and look at some of the techniques already submitted by some pioneers.

(Thanks @Suvrutt_Gurjar !)

[Suvrutt_Gurjar]

Hi @TeeSee1 ,

Thank you.

Yes, I deleted the post because after rereading @Adolfo_Enrique_ ' s post, I thought I misunderstood  his requirement. After rereading I concluded, he is probably looking for creating a numeric list rather than finding the index of an element in a list that I responded with.

Anyway, let us await further response from @Adolfo_Enrique_ 

[Adolfo_Enrique_]

hello everyone, first of all thank you very much for your help. @Suvrutt_Gurjar , @TeeSee1 

What I need is, starting from a list with n values, to obtain a list with the position that each of the values ​​occupies. I am not doing a search for a particular value, simply, if the list is for example LIST(A,B,C,X,Y,Z) , get a list with each of the positions, in the case of the example the the result will be LIST(1,2,3,4,5,6).

[Suvrutt_Gurjar]

@Adolfo_Enrique_ 

How many elements the list is likely to have? In 10s or 100s or 1000s

Accordingly the community could suggest a most appropriate solution if available.

[Adolfo_Enrique_]

no more than 10 elements

[Suvrutt_Gurjar]

Your expression for the numeric list can be something like 

LIST(LEFT(LIST(1,2,3,4,5,6,7,8,9,10), FIND(COUNT([Fruits List]), LIST(1,2,3,4,5,6,7,8,9,10))))

Assumes the [Fruits List] will never be empty. Or some more expression may need to be added to take care of empty [Fruits List].

[Steve]

Why would you want to do this?

[Adolfo_Enrique_]

Hello Steve.
I tell you, I need to be able to select elements from a list and then to the selected element, indicate the position in which that element will take. For example, if I have the list fruits(apples, pears, bananas), I can obtain from the list fruits, a list called posfruit(1,2,3) posfruit is obtained from the list fruits, in this way if the fruit list has 5 elements, posFruit will be posFruit(1,2,3,4,5) My idea is to have a screen with two combo boxes. one to select elements from the fruit list and another combo box to indicate in which position I am going to place the selected fruit, regardless of the position of the selected fruit.

In this way, for example, from the fruit list, I will be able to select the value apples, and from posFruit select 3. In this way I will be able to indicate the order that the fruits will occupy, regardless of the position they occupy in the fruits list.

I hope you understand what I need to do.