What does the set -x command do in LabTalk Origin2015

Question

I have to maintain an old program that uses a LabTalk script to draw some charts. This script that does not run correctly. Since I am a total beginner with Origin Labtalk I have the following question: My code opens 2 data-sources and is supposed to draw the data into 1 graph. When I execute my code it opens an empty graph.

%A=C:\A_Grid#2a.dat;
%B=C:\A_Grid#2b.dat;   
xn= 41;
...
window -a Data1;
for (i=1;i<=xn;i+=1) {
   worksheet -t $(i*2-1) 4;
   worksheet -n $(i*2) B$(i);
   worksheet -n $(i*2-1) A$(i);
}
window -i;
window -a Data2;
for (i=1;i<=yn;i+=1) {
   worksheet -t $(i*2-1) 4;
   worksheet -n $(i*2) B$(i);
   worksheet -n $(i*2-1) A$(i);
}
window -i;
window -a Plot;
for (i=1;i<=xn;i+=1) {
   %k=Data1_B$(i);
   set %k -x Data1_A$(i);     // without these lines it works but Why?
   layer -i %k;
}

for (i=1;i<=yn;i+=1) {
   %k=Data2_B$(i);
   set %k -x Data2_A$(i);    // without these lines it works but Why?
   layer -i %k;
}

When I leave out the following lines, it works.

set %k -x Data1_A$(i);

.

set %k -x Data2_A$(i);  

Does anybody know

1. what this line is supposed to do?
2. What the set-command is?
3. What -x means ?

Thanks for your help.

itelly

Answer 1

In your example the command sets the values of Data1_A1, Data1_A2, etc. as X values for the Y value datasets Data_B1, Data_B2, etc.

-x value; Associate an X dataset with a Y dataset

Syntax: set -x value

Associate an X dataset with a Y dataset. Value must be a dataset name and serves as the X values for the dataset name. A graph window must be the active window. Value can refer to any dataset.

More information about the set command can be found here.