Yes,
for vgs=1:1:2
for vds=1:1:2
%....
end
end
As you assigned input gate voltage (vgs) and output drain voltage (vds) in the for loop assignment. During execution it assign a single value only, like 1 or 2, when the loop execution completed it rflects with last value.
See the following example
>> vgs=1:1:2;
>> disp(vgs)
1 2
In for loop
for vgs=1:1:2
%code
end
#Result
>> disp(vgs)
2
Please go through Matlab Basics
