Spline interpolation in matlab

I have the following:

    x = 1:365;
    y = T;
    xx = missing;
    yy = interp1(x,y,xx,'spline')

I have data `T`, which is 365 days of data, and `missing` is a vector containing the days on which the data is faulty. I need to generate estimated values at the missing days. However, when I use the above syntax, it returned a vector of all the same value. I made some changes, got an error, deleted them, and now with the same syntax I'm getting the error on line 4:

    You can not subscript a table using only one subscript. Table subscripting
    requires both row and variable subscripts.

What am I doing wrong?

[Christiaan]

Dear Rachel,

Could you send us the mat-file of 'T' and 'missing'? A small example, how the interp1 function works, I have posted below for you.

clc; clear all; close all;
x = 1:365;
y = sin(x);
xx = [1 3 4];
yy = interp1(x,y,xx,'spline')

Kind regards, Christiaan

[Rachel Chung]

here's the file!

Answer 1

[dpb]

Your T vector has zero-valued entries for the missing locations and so there is a data value at that day and therefore interp1 returns that value (0) instead of an interpolated value.

T(missing)=[];           % remove the missing locations
t=1:365; t(missing)=[];  % the correlating full day vector
yy=interp1(t,T,missing,'spline')