Calculate the elastic modulus from raw CSV separated data from instron tests

calculateElasticModulusInstron.m

function calculateElasticModulusInstron(x,y)
    %%%% Compute the elastic modulus from experamental data.
    %%%% INPUT VARIABLE DEF: x=load of sample from experamental data, 
    %%%%                     y=elongation of sample from experamental data.

    %%prep matlab environment:
    clc; clf;

    %% Define length of the slope which you want to calculate Elastic Modulus for:
    lengths1 = 300:1800;
    
    %% Select input data:
    x = x(lengths1); 
    y = y(lengths1);

    %Best fit line math:
    p = polyfit(x,y,1);   % p returns 2 coefficients fitting r = a_1 * x + a_2
    r = p(1) .* x + p(2); % compute a new vector r that has matching datapoints in x

    %% now plot both the points in y and the curve fit in r
    plot(x, y, 'x'); % raw data
    hold on;
    plot(x, r, 'r-','LineWidth',4.3); % calculated line of best fit
    hold off;
    ElasticModulus=p(1) %print elastic modulus (slope)
end