# Make a plot using value from a certain line of matrix

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Huichen Zhang on 8 Oct 2016
Commented: dpb on 8 Oct 2016
Suppose I have a matrix of dimension 10x10. Now I want to use the value along the column 5 as Y axis, and use the index of rows to represent x increment, how can I make a plot like that in Matlab? And at the same time, when I do the contour plot of a matrix, is it a way to indicate the highest and lowest value in the contour plot?

Massimo Zanetti on 8 Oct 2016
Edited: Massimo Zanetti on 8 Oct 2016
Herre it is:
%define a 10x10 matrix
A=rand(10,10);
%plot its 5th column with index as x axis
plot(A(5,:));
%detect min and max
[minv,imin]=min(A(5,:));
[maxv,imax]=max(A(5,:));
hold on;
plot(imin,minv,'*',imax,maxv,'d');
legend('line','min','max')
hold off;
dpb on 8 Oct 2016
plot(A(5,:));
NB: that this is 5 th row, not column...it's row 5, all columns; the indices are reversed regarding the question posed.

dpb on 8 Oct 2016
1. plot(Y(:,5))
2. clabel(C,h,[v(1) v(end)])