data = load(' loa . txt ')； % read data
X = data (:,1)'; % assigns the first column to x and turns it into a row vector.
Y = data (:,2)'; % assigns the second column to y and turns it into a row vector.
Plot(x, y,' *')% drawing
Keep? exist
b=polyfit(x，y，6)； % for six times, you will find that your fitting image is irregular, so the fitting times can be larger, depending on your own meaning, and b is the value before polynomial. Just like the values of y = ax+b, a and b in quadratic fitting.
yy=polyval(b，x)； % to get the new value of y after fitting.
Plot(x, yy)% draw fitting diagram.