How to apply a condition of a list of numbers

I do not see the error you are sharing:

a!localVariables(
  local!variable: { 2017, 2018, 2019, 2020 },
  local!variable2: a!forEach(
    items: local!variable,
    expression: if(fv!item < 2018, "PRE-YEAR", fv!item)
  ),
  local!variable2
)

...results in:

This is the initial data that is list of dictionary and i Need result in list of numbers

arshbirs0002 said:

{"PRE-YEAR",2018,2019,2020}

You said this is what your result needed to be like...by definition it cannot be a list of numbers since your code is outputting "PRE-YEAR" when the item in your list is < 2018.

...just trying to understand your response...are you saying that the input to your rule is a list of Dictionary, but that you want to examine the value of each item as per your original code...that is, something like this:

a!localVariables(
  local!variable: { 
    { EOMYear: 2017 },
    { EOMYear: 2018 },
    { EOMYear: 2019 },
    { EOMYear: 2020 },
    { EOMYear: 2021 }
  },
  a!forEach(
    items: local!variable,
    expression: if(
      fn!tointeger(fv!item.EOMYear) < 2018,
      "PRE-YEAR",
      fv!item.EOMYear
    )
  )
)

...which results in:

Hello friend, 

You are very close to your solution! 

the error you are receiving is due to the comparison operand. You should just be able to do: if( to integer(fv!item) < 2018, "pre", fv!item)

Furthermore, based on your output, it seems that you are doing this in an expression rule, so you'll have to return the value on it's own or as the name of the variable, please see below the code snippet: 

-- Start

local!variable: {2017, 2018, 2019, 2020}

local!variable2: a!forEach(
    items: local!variable,
    expression: if( tointeger(fv!item) < 2018, "PRE-YEAR", fv!item)
),

/*return */ 

local!variable2

-- End

If this is the value you need to return, you can go without the local variable 2 and just explicitly do the a!forEach at the end of the rule, but if it's not, that should resolve your issue! Best wishes.