Make discontinuous data continuous

I have the following 2 arrays:

    x = [0  450  1200  5000  9000  14000  20000]
    y = [-23  6  -1  8  -8  1  -20]

I would like to interpolate on the x axis to get a total of 256 y values.

I've tried using y(index) but the problem there is that my x-axis data is discontinuous. Using the index function where Y is not already defined returns

    Empty matrix: 1-by-0

Is there any way to connect each point to create a continuous distribution so I can use the index function?

Answer 1

[Stephen23]

>> xi = [0,450,1200,5000,9000,14000,20000];
>> yi = [-23,6,-1,8,-8,1,-20];
>> xo = linspace(xi(1),xi(end),256);
>> yo = interp1(xi,yi,xo);
>> yo(:)
ans =
-23.000000
-17.945534
-12.891068
 -7.836601
 -2.782135
  2.272331
  5.807843
  5.075817
  4.343791
  3.611765
  2.879739
  ... lots more here
-16.156863
-16.431373
-16.705882
-16.980392
-17.254902
-17.529412
-17.803922
-18.078431
-18.352941
-18.627451
-18.901961
-19.176471
-19.450980
-19.725490
-20.000000