try-catch lasterr

Num = 6;
Mat = magic(4)
try 
    Mat_Num = Mat(Num,:)
catch
    Mat_end = Mat(end,:)
end
lasterr

运行结果

>> ex4_7

Mat =

    16     2     3    13
     5    11    10     8
     9     7     6    12
     4    14    15     1


Mat_end =

     4    14    15     1


ans =

试图访问 Mat(6,:)；由于 size(Mat)=[4,4]，索引超出范围。