Base Rule
=====================================
with(
  local!indexOfField:wherecontains(
    ri!field,
    ri!listOfFields
  ),
  if(
  or(
    isnull(ri!field),
    rule!APN_isEmpty(ri!valuesForTheField)
    ),
    {},
    choose(
      local!indexOfField,
      {a:ri!valuesForTheField},
      {b:ri!valuesForTheField},
      {c:ri!valuesForTheField},
      {d:ri!valuesForTheField},
      {e:ri!valuesForTheField}
    )
)
)

Update CDT At Given Index
====================================
updatecdt(
  ri!cdt,
  ri!fieldAndValue
)



Main Rule
=====================================
load(
  local!test: {
    {
      a: 1, b: 2,c: 3,d: 4,e: 5},
    {
      a: 11,b: 12,c: 13,d: 14,e: 15},
    {
      a: 21,b: 22,c: 23,d: 24,e: 25},
    {
      a: 31,b: 32,d: 34,e: 35},
    {
      a: 41,b: 42,c: 43,d: 44,e: 45}
  },
  local!fieldsAndValues: apply(
    rule!baseRule(
      field: _,
      valuesForTheField: _,
      listOfFields: {
        "a","b","c","d","e"}
    ),
    merge(
      {
        "b","d","e"
      },
      {
        52,54,55
      }
    )
  ),
  reduce(
    rule!updateCdtAtGivenIndex,
    local!test[ri!index],
    local!fieldsAndValues
  )
)