First of all, thanks for all the replies!!
What you have written helps, but is not entirely the answer to my problem.
What I'd have is the creation of new data.frames each of one named with
the ID of the original dataframe and with all the columns.
For example, in the original dataframe one column (ID) has 5 different
elements:
ID value1 value2
x1 10 12
x1 12 22
x1 11 9
x2 15 10
x3 11 11
x3 13 8
I need a command ables to split the dataframe in other smallest and
separated dataframes, so that they look like
x1 is
ID value1 value2
x1 10 12
x1 12 22
x1 11 9
x2 is
ID value1 value2
x2 15 10
and x3 is
ID value1 value2
x1 10 12
x3 11 11
x3 13 8
Sorry if I'm not able to explain it better and as I said I'm very new to
R.....
Thanks
Matteo