How to zoom a region of a plot?

I have a program which plots 6 different data as separate plots. I want to get those plots zoomed in a range. For example, my original data X value range from 0 to 5e5. I want only data from 0 to 0.2e5 appear on my plot, I mean zoomed in this region. How can I modify my script to do this?

My program:

 A=load('31March2014e_run1.asc');
 B=load('31March2014e_run2.asc');
 C=load('31March2014e_run3.asc');
 D=cat(1,A,B,C);
 x=D(:,1);
 n=6.5:1000:2e6;
 y=hist(x,n);

 semilogy(n,y,'-ob')

I tried by giving

 samplerange=0:0.2e5

then modifying

 semilogy(n(samplerange),y,'-ob')

But it doesnt work!

Answer 1

[Azzi Abdelmalek]

 ylim([0 0.2e5])