How to achieve this simple Column addition in JSL?

[Fred Zhang <ieaggie2009@gmail.com>]

Hi,

 

Just a newbie of JSL.

 

I open a data tabel (each column is numeric type).

And want to add up each other column to a new column "sum".

Given the following script, I always get the Log Comment:

invalid argument in access or evaluation of 'Column' , Column( dt, j )

Can anyone help me out?

Thanks, Fred

dt = currentdatatable();
nc = ncol(dt);
nr = nrow(dt);
show(nr);show(nc);
sumcol = dt << newcolumn("sum", numeric);
for(i=1, i<=nc, 1,
 for(j=1, j<=nr, 2,
  sumcol[i] += column(dt, j)[i];
 )
)