Save only updated data from a given array

What did you try so far? I mean, this is not more than a foreach() on the your final data, and a condition to either include or exclude the data from the resulting list.

HI [mention:29737913d085458190bfc861db9c1d95:e9ed411860ed4f2ba0265705b8793d05] ,

 As per my understanding you need only the data that is modified to store. You can use the difference() to get the modified data.

The below code might help.

a!localVariables(
  local!options:{"Yes","No"},
  local!originalGridData:a!refreshVariable(
    value: {
      a!map(id:"1",date:date(2025,1,15)),
      a!map(id:"1",date:date(2025,1,16)),
      a!map(id:"1",date:date(2025,1,14)),
      a!map(id:"2",date:date(2025,1,17)),
      a!map(id:"2",date:date(2025,1,15)),
    },
    refreshOnReferencedVarChange: false()
  ),
  local!changedData,
  local!finaldata:local!originalGridData,
  {
  a!gridLayout(
    headerCells: {
      a!gridLayoutHeaderCell(label:"Id"),
      a!gridLayoutHeaderCell(label:"Date"),
    },
    columnConfigs: {
      a!gridLayoutColumnConfig(width: "DISTRIBUTE"),
      a!gridLayoutColumnConfig(width: "DISTRIBUTE"),
    },
    rows: a!forEach(
      items: local!finaldata,
      expression: a!gridRowLayout(
        contents: {
         a!textField(
           value: fv!item.id,
           saveInto: fv!item.id
         ),
         a!dateField(
           value: fv!item.date,
           saveInto: fv!item.date
         )
        }
      )
    ),
  ),
  a!buttonArrayLayout(
    buttons: {
      a!buttonWidget(
        label:"Save",
        saveInto: {
          a!save(local!changedData,difference(local!finaldata,local!originalGridData))
        }
      )
    }
  ),
  /*Changed data*/
  a!gridField(
    data: local!changedData,
    columns: {
      a!gridColumn(
        label:"Id",
        value: fv!row.id
      ),
      a!gridColumn(
        label:"Date",
        value: fv!row.date
      )
    },
    borderStyle: "STANDARD"
  )
  }
)