Make a plot using value from a certain line of matrix

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?

Answer 1

[Massimo Zanetti]

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,:));
%add them to plot
hold on;
plot(imin,minv,'*',imax,maxv,'d');
legend('line','min','max')
hold off;

[Huichen Zhang]

Thank you so much!

[Massimo Zanetti]

To plot the contour

[C,h] = contour(A);
clabel(C,h);

[dpb]

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.

Answer 2

[dpb]

1. plot(Y(:,5))
2. clabel(C,h,[v(1) v(end)])