How to interpolate based on the first column in a matrix and fill the interpolated rows of the other columns with set values?

Hello,

I am trying to interpolate between values in column 1 of an nX8 matrix. I want the interpolation step to be constant (e.g. step size = 1). I want to start at 0 and go up to the first value in column 1, then add the correct values in between successive rows. I want to insert these interpolated values into the original nX8 matrix, but I want to specify values for the rest of the inserted row (i.e. the remaining 7 elements in the row) to be a mixture of zeros or NaNs (it would be the same for every row). Here is an example of what I am trying to do but with fewer columns:

example =    [3.0000    0.9172    0.3804    0.5308    0.5688
              5.0000    0.2858    0.5678    0.7792    0.4694
              7.0000    0.7572    0.0759    0.9340    0.0119
              10.0000    0.7537    0.0540    0.1299    0.3371];

%...Code to do the job...

result =    [0.0000    NaN       NaN       0         NaN
             1.0000    NaN       NaN       0         NaN
             2.0000    NaN       NaN       0         NaN
             3.0000    0.9172    0.3804    0.5308    0.5688
             4.0000    NaN       NaN       0         NaN
             5.0000    0.2858    0.5678    0.7792    0.4694
             6.0000    NaN       NaN       0         NaN
             7.0000    0.7572    0.0759    0.9340    0.0119
             8.0000    NaN       NaN       0         NaN
             9.0000    NaN       NaN       0         NaN
             10.0000    0.7537    0.0540    0.1299    0.3371];

Thanks!

Answer 1

[Matt J]

example =    [3.0000    0.9172    0.3804    0.5308    0.5688
              5.0000    0.2858    0.5678    0.7792    0.4694
              7.0000    0.7572    0.0759    0.9340    0.0119
              10.0000    0.7537    0.0540    0.1299    0.3371];

step=1;
fill=[ NaN       NaN       0         NaN];


first=( 0:step:max(example(:,1)) ).';
n=numel(first);
result=[first, repmat(fill,n,1)];

 [tf,loc]=ismembertol(example(:,1),first);
 
 result(loc(tf),:)=example(tf,:)

result = 11×5

0 NaN NaN 0 NaN 1.0000 NaN NaN 0 NaN 2.0000 NaN NaN 0 NaN 3.0000 0.9172 0.3804 0.5308 0.5688 4.0000 NaN NaN 0 NaN 5.0000 0.2858 0.5678 0.7792 0.4694 6.0000 NaN NaN 0 NaN 7.0000 0.7572 0.0759 0.9340 0.0119 8.0000 NaN NaN 0 NaN 9.0000 NaN NaN 0 NaN

[ForHim]

Thanks!