need help for nested list data Updation

hi, 

I have an editable grid and save the selected rows in the a variable local!selectedrows,

has fields {id:1, name:"test1, age:"60"

                 {id:2,name:test1,age:"70"}

have another variable 

local!displayitems has a nested list . 

  {id:2,name:test1,age:"70"} is present inside the second index and 5 th item 

please suggest how to write code for this.  my intent is i have to update the selected Row into the display items by indexing it upon button click.