error using subplot,index exceed numbers of subplots

x=1:1:10 for i=2:2:8 y=4*x-3*i subplot(4,1,i) plot(x,y) end

why do i keep getting this error- error using subplot,index exceed numbers of subplots

Answer 1

[Christopher Jones]

Your subplot only has 4x1 subfigures ie 4 with indexes 1,2,3,4

Your index vector i on the other hand tries to access 2,4,6,8.

Two of those indexes (6,8) don't exist and exceed the number of subplots.

To quickly fix the problem just change the for argument to i=1:4 and add a *2 to the y function

figure; 
x=1:1:10 
for k=1:4
    i = k*2;
    y=4*x-3*i; 
    subplot(4,1,k); 
    plot(x,y) ;
end

Answer 2

[Jos (10584)]

A general solution that loops over the values using a separate index:

x=1:1:10 
value = 2:2:8
N = numel(value) 
for k = 1:N
  y=4*x-3*value(k)
  subplot(N,1,k) 
  plot(x,y)
  title(sprint('Value #%d : %d',k,value(k))) ; % add a title
end