Only fields with scalar types can be indexed from an array.

RE: Only fields with scalar types can be indexed from an array.

Peter Lewis — Thu, 09 Apr 2020 13:24:59 GMT

You might need to do something with a!forEach() and update just the value of interest. For example, suppose I want to update the list for the second item - here's an expression that might work:

a!localVariables(
  local!test: {
    'type!{urn:com:appian:types:PDL}PDL_TestNestedCDT'(
      list:{1,2,3}
    ),
    'type!{urn:com:appian:types:PDL}PDL_TestNestedCDT'(
      list: {4,5,6}
    )
  },
  {
    a!richTextDisplayField(
      value: tostring(local!test)
    ),
    a!buttonArrayLayout(
      buttons: {
        a!buttonWidget(
          label: "Test",
          saveInto: a!save(
            target: local!test,
            value: a!forEach(
              items: local!test,
              expression: if(
                fv!index = 2 /* only update row 2 */,
                'type!{urn:com:appian:types:PDL}PDL_TestNestedCDT'(
                  list: {7,8,9}
                ),
                fv!item
              )
            )
          )
        )
      }
    )
  }
)

RE: Only fields with scalar types can be indexed from an array.

Shubham Aware — Thu, 09 Apr 2020 09:28:21 GMT

Hey Peter,
I am able to print by using this

index(index(local!test, 1, {}), "list")

But i am facing difficulties in writing because

I can write to it like local!test[1].list

Can you suggest something?

RE: Only fields with scalar types can be indexed from an array.

Shubham Aware — Thu, 09 Apr 2020 05:47:27 GMT

Thanks Peter
It's working now

RE: Only fields with scalar types can be indexed from an array.

Peter Lewis — Wed, 08 Apr 2020 22:20:04 GMT

Usually this happens if you have an array of arrays. Is it possible that local!gridDataStructure also contains an array of CDT? Here's an example:

a!localVariables(
  local!test: {
    'type!{urn:com:appian:types:PDL}PDL_TestNestedCDT'(
      list:{1,2,3}
    ),
    'type!{urn:com:appian:types:PDL}PDL_TestNestedCDT'(
      list: {4,5,6}
    )
  },
  index(index(local!test, 1, {}), "list")
)

This will work because I first index into the first item of "PDL_TestNestedCDT", then index into "list". However, it wouldn't be possible to directly enter local!test.list because that results in a list of lists.

If you need to display or perform a calculation with this, you can also get around this by using a!forEach() like this:

a!localVariables(
  local!test: {
    'type!{urn:com:appian:types:PDL}PDL_TestNestedCDT'(
      list:{1,2,3}
    ),
    'type!{urn:com:appian:types:PDL}PDL_TestNestedCDT'(
      list: {4,5,6}
    )
  },
  a!forEach(
    items: local!test,
    expression: fv!item.list
  )
)

RE: Only fields with scalar types can be indexed from an array.

Danny Verb — Wed, 08 Apr 2020 21:18:38 GMT

Can you also attach the SAIL used to index into the CDT?