Subscript range issue when doing increasing for loop

dadawasozo

I got error "Subscript Range in access or evaluation of 'collist[ /*###*/i]' , collist[/*###*/i]" when doing a simple new column () with increasing for loop. I able to solve it using decreasing for loop. However, I want to have created column ordered follow increasing for loop. I dont understand what causes the error when using increasing for loop here. Can someone provide suggestion how I can use increasing for loop here? if possible, can someone help explain why the error will happen for increasing for loop?

path = "my file path with filename.jmp";

dt= open(path);
collist = dt <<get column names(string);
colname = Column("test1") <<getname;
colnumber = (Loc(collist,colname))[1];

For(i=colnumber+1, i<=Ncols(dt),i++,  //give the error
//For(i=Ncols(dt), i>colnumber+1,i--,  fixed issue but created column order inverted

dt  <<new column("SG_"||collist[i], character);

);

Thierry_S

Hi,

I think that your problem is that N Cols (dt) increases after each iteration of your loop. Therefore, your index value "i" exceeds the number of elements in your collist list.

 

I suggest capturing the number of columns in dt outside the loop and using it as a fixed limit. 

path = "my file path with filename.jmp";

dt= open(path);
collist = dt <<get column names(string);
colname = Column("test1") <<getname;
colnumber = (Loc(collist,colname))[1];
num_col = N Cols (dt);

For(i=colnumber+1, i<=num_col,i++,  
   dt  <<new column("SG_"||collist[i], character);

);

Of note, I am unsure why the reverse loop works. You it should run into a similar issue with your collist variable.

Let us know if that solve your issue.

Best,

TS