Remove duplicate values in Editable grid

Question

Hi All, 
 I have a scenario like 
 I have a drop down in editable grid, 
 1st i I add a value through dropdown, 2nd time when I add a value if I select the same value as first it should throw validation error, saying duplicate value found please remove. 
 Can you please suggest me,how can I reach this approach. 
 
 Thanks 
 Divya K

Dude · Answer

To avoid duplicate use union(array1,array2). Use it in a!save() along with append()

Mike Schmitt · Answer

Hi, 
 Someone else asked a somewhat-similar question just a few days ago , and I provided an example implementation where subsequent rows don't even get the option of duplicate dropdown values (though just validating against duplicate choices would also be possible). I encourage you to check it out and see if it gives you any ideas.