How to reject values in a CDT array on the basis of a condition?

RE: How to reject values in a CDT array on the basis of a condition?

Mike Schmitt — Tue, 08 Sep 2020 12:24:01 GMT

FYI, I've noticed this before as well, and more recently I've figured out that wrapping the entire a!forEach() statement in a!flatten() also handles this scenario (with much less bad taste in the back of my mouth than using the old looping functions).

(In fact, I was considering including it in my answer above, but I thought for the moment it might be better to not over-complicate things.. now i'm not so sure)

RE: How to reject values in a CDT array on the basis of a condition?

varunkumarb0001 — Mon, 07 Sep 2020 10:24:22 GMT

Chris Mike Schmitt Stefan Helzle

Thanks everyone for the elaborate responses. The solution provided worked.

RE: How to reject values in a CDT array on the basis of a condition?

Stefan Helzle — Sat, 05 Sep 2020 12:36:00 GMT

May I indicate one issue with the foreach-filter habit. In case no item matches the condition, the created list is a list of empty lists {{}, {}, {}, ...}. This can break any subsequent code and can be a pain to debug. This is why I still recommend the "old" looping functions filter() and reject() and asked Appian to come up with new filter functions similar to a!foreach().

RE: How to reject values in a CDT array on the basis of a condition?

Mike Schmitt — Fri, 04 Sep 2020 17:30:23 GMT

wow/ouch ;-)

RE: How to reject values in a CDT array on the basis of a condition?

Chris — Fri, 04 Sep 2020 16:37:18 GMT

You may! I agree with the a!forEach() replacement. Still kicking the bad apply() habit.. Heck, we still have doForEach in a few older Portal PMs circa 2010 ;)

RE: How to reject values in a CDT array on the basis of a condition?

Mike Schmitt — Fri, 04 Sep 2020 15:52:05 GMT

a!forEach() handles this more gracefully, IMHO, and allows us to skip the awful deprecated "apply()" function.

(If I may borrow your original code..)

a!localVariables(
  local!data: {
    {a: 1, b: null},
    {a: null, b: null},
    {a: null, b: 1},
    {a: 1, b: 2},
    {a: 2, b: null}
  },
  
  a!forEach(
    items: local!data,
    expression: if(
      isnull(fv!item.a),
      {},
      fv!item
    )
  )

  /*index(*/
    /*local!data,*/
    /*wherecontains(*/
      /*reject(*/
        /*fn!isnull,*/
        /*local!data.a*/
      /*),*/
      /*apply(fn!tointeger,local!data.a)*/
    /*)*/
  /*)*/
)

RE: How to reject values in a CDT array on the basis of a condition?

Chris — Fri, 04 Sep 2020 15:35:57 GMT

Try something like this. Note in the wherecontains() you may have to change the apply(fn!tointeger..) to match your data type, as wherecontains() is type-sensitive.

a!localVariables(
  local!data: {
    {a: 1, b: null},
    {a: null, b: null},
    {a: null, b: 1},
    {a: 1, b: 2},
    {a: 2, b: null}
  },
  
  index(
    local!data,
    wherecontains(
      reject(
        fn!isnull,
        local!data.a
      ),
      apply(fn!tointeger,local!data.a)
    )
  )
)