Finding a value in a column from a change in another column in a matrix?

Given the matrix below:

    1.1586    0.9381    3.0000         
    1.2265    0.6906    3.0000       
    1.2765    0.5432    3.0000        
    1.3266    0.4243    2.9999        
    1.3766    0.3302    2.9999      
    1.4267    0.2565    2.9997

How can I write the code which gives me the value in column 1, corresponding to the point in which column 3 changes from 3.0000 to 2.9999?

Answer 1

[Thorsten]

ind =  X(:,3) == 3.0 & [abs(abs(diff(X(:,3))) - 1e-4) < 1e-10; 0]
X(ind,1)

or

ind =  X(1:end-1,3) == 3.0 & X(2:end,3) == 2.9999;
X(ind, 1)

[Matilde Garcia]

Thanks for the help

Answer 2

[Eng. Fredius Magige]

Hi Use for in association with find function looking exact Nii_Ni=0.0001; note the last and first N need some manipulation, this could be controlled by if else