Save row values of one CDT as column values of another CDT

a!save( 
    CDT2,
    update(
        data: CDT2,
        index: a!forEach(
            items: CDT1.fieldSeq,
            expression:choose(key: fv!item, choice1: "value1", choice2: "value2"...),
        )/* a!forEach returns a list, in this case a list of indeces */
        value: CDT1.fieldValue /*list of values goes into list of indeces*/
    )
)

Bear in mind this is pseudo-code that I'm not trying to test out with the above scenario.  Also keep in mind that choose function requires that every value from 1 to n be represented.  If you have a 5, you also must have 4, 3, 2, and 1.  You can't skip any.  It doesn't look like you do, so it's a good use case for choose.

Let us know if it works.

Hi Dave,

Thank you for your suggestion.

I had few queries more related to the same.

1. For choose, I want to use an iterative value as my choice values because sometimes CDT1 can have 5 items, sometimes 3, sometimes 20 or more. No constant value for the number of items in CDT1.

2. Also CDT2 will be null in starting. As an user inputs value in form that shows data from CDT1, the row would get added in CDT2.

Any suggestions on the above will help me out!!
Appian version I use is 21.1 and we do not have update() function in it.

Thanks in advance!

Choose should work fine so long as you have the maximum possible value in the choose function.  It is iterative in a sense, because for each individual value, you pick the location to save to in CDT 2.  So if you have sequences 5, 17, 4, as long as the choose goes at least up to 17, the forEach loop will return "value5", "value17", "value4". 

Now, if the name of the place that you're supposed to save a "5" changes depending on the size of the CDT, that's a nightmare I don't want to think about right now.  In that case, you might have to create a gigantic if() nest, or if the sets of possibilities is finite in length, you might consider a Decision object.

Also, you can use updateCDT to achieve similar effect, but a!update is better.  You'll probably have to a!forEach to create each individual updateCDT statement.  Consider upgrade, or telling others that you should upgrade.

Choose should work fine so long as you have the maximum possible value in the choose function.  It is iterative in a sense, because for each individual value, you pick the location to save to in CDT 2.  So if you have sequences 5, 17, 4, as long as the choose goes at least up to 17, the forEach loop will return "value5", "value17", "value4". 

Now, if the name of the place that you're supposed to save a "5" changes depending on the size of the CDT, that's a nightmare I don't want to think about right now.  In that case, you might have to create a gigantic if() nest, or if the sets of possibilities is finite in length, you might consider a Decision object.

Also, you can use updateCDT to achieve similar effect, but a!update is better.  You'll probably have to a!forEach to create each individual updateCDT statement.  Consider upgrade, or telling others that you should upgrade.