How to keep only unique items based on the specific key. In this case countryId . Data type is List of Dict

a!localVariables(
  local!test1: {
    {
      item: "stapler",
      name: "Mike",
      countryId: 1
    },
    {
      item: "printer",
      name: "Larrys",
      countryId: 2
    },
    {
      item: "printer",
      name: "Larry",
      countryId: 2
    },
    {
      item: "laptop",
      name: "Mike",
      countryId: 1
    },
    {
      item: "glass",
      name: "Mike",
      countryId: 3
    }
  },


  a!forEach(
    items: union(local!test1.countryId,local!test1.countryId),
    expression: displayvalue(
      fv!item,
      local!test1.countryId,
      local!test1,
      null
    )
  )
)

a!localVariables(
  local!test1: {
    {
      item: "stapler",
      name: "Mike",
      countryId: 1
    },
    {
      item: "printer",
      name: "Larrys",
      countryId: 2
    },
    {
      item: "printer",
      name: "Larry",
      countryId: 2
    },
    {
      item: "laptop",
      name: "Mike",
      countryId: 1
    },
    {
      item: "glass",
      name: "Mike",
      countryId: 3
    }
  },


  a!forEach(
    items: union(local!test1.countryId,local!test1.countryId),
    expression: displayvalue(
      fv!item,
      local!test1.countryId,
      local!test1,
      null
    )
  )
)

Wow! you're amazing. Could you please explain the expression section?

From Appian docs, displayvalue: "Tries to match a value in a given array with a value at the same index in a replacement array and returns either the value at the same index or a default value if the value is not found."

https://docs.appian.com/suite/help/23.3/fnc_conversion_displayvalue.html

So it is like: Iterate on unique countries, find the index of the first item in the list of ALL the countries, and return the full record at that same index.

This is a great function once you understand how it works!

Thank you so much !. I really appreciate it. I will try to play around and familiar with this function.