how can I let the string variable change in a loop

Dear fellows,

I am trying to plot the scatter for a set of vectors. My secource file pf.mat is a 65*154 matrix. I want to plot two columns each time so I am writing a loop (i=1:77)from 1 to 77. In each loop, after plot the vectors, I would to save the image as the number of the i. My questions is how do I name the image then it can change as th loop goes on? My current code only can save the image as the letter i, but not the actual number of i. Here is my code

if true
  % load pf
for i=1:77
scatter(pf(:,(2*i-1)),pf(:,2*i),'.')
hold on
plot([0,100],[100,0])
h(i)=scatter(pf(:,(2*i-1)),pf(:,2*i),'.');
saveas(h(i),'i', 'pdf')

end end

Answer 1

[Iain]

try using num2str(i) instead of 'i'.