Vectors must be the same length

my code says "vectors must be the same length" really new to matlab.

load("lnu (1).mat")
plot(xy,'.');
axis equal;
hold on
s=[1 0;0 -1];
b=xy'*s;
t=[cos(2*pi/3) -sin(2*pi/3);sin(2*pi/3) cos(2*pi/3)];
a=xy'*t;
plot(xy,a,b,'.');
axis equal;

Answer 1

[Voss]

plot takes vectors in pairs of arguments, like plot(x1,y1,x2,y2, ...)

The second call to plot in your code uses three numeric arguments, so plot's going to treat xy as a vector of x-values and a as a vector of corresponding y-values, but I suspect that they don't have the same number of elements. (Can't say for sure because I don't have the data, but this is a guess based on the error message.)

Try splitting the variable xy into its x and y parts and send it as two consecutive arguments in both calls to plot, e.g., plot(xy(:,1),xy(:,2)) or plot(xy(1,:),xy(2,:)), depending on how xy is arranged (again, can't say for sure without the data.)