How to evaluate a matrix on the fly?

Question

I am sure there is a simple answer to this problem but I can't figure it out.  I am trying to compute distance between two objects using a distance matrix.  I can't get the following JSL code to work:

dt = Open (dist matrix.jmp);

m = dt << Get All Columns As Matrix();

dt2 = Open(students.jmp);

col = Column("Prefect No");

B=col<<Getasmatrix;

n=nrow(dt2);

a=j(n,1,0);

for(i=1,i<=n, i++, a=m[b,4]);

show(a);

I keep getting an error when evaluating m[,].  I tried Eval and other things but it doesn work.

Can anyone help?

todds · Answer

I saved my dataset back to excel and brought it back into JMP.  Now that dataset when is made into a matrix is in the correct order.  I must have reset the default order of the columns when I recreated it in JMP.  So now everything works.  Thanks for the help.

mikedriscoll · Answer

Got an example data set? I had one and tried the following code, and it had the correct order.  It replaced character values with '1's though, which is along the lines of what I'd expect.

dt = current data table();

m = dt << Get All Columns As Matrix();

show(m);

todds · Answer

I figured out what the main error was.  Some of the rows had missing values and when JMP tried to evaluate the missing subscript it bombed.  So I used the following code:

for(i=1,i<=n, i++, if((not(is missing(A[i]))), C[i]=m[A[i],8], C[i]=.));

It works fine.

Now my only issue is that when I use

m = dt << Get All Columns As Matrix();

The subsequent matrix m is not in the order that I have it in the dataset.  So trying to figure out how to keep the original order.  Any ideas?