Hi friends,

I have a dataframe

Column1 Column2

A 12

A 4

B 5

B 7

C 3

D 4

And ı want to use "group by"

Then ı want new dataframe like belove

Column1 Column2

A 16

B 12

C 3

D 4

E N/A or 0

But there is no "E" row in the first database.

How do ı add "E" row .while using "group by..

Just A,B,C,D are seen. İn the first dataframe"...

Is it possible in R?

How can we code it in R language?

Thanks for your help.