Get a value of non existant index of array by interpolation

Im trying to remember a function in Matlab which returns a value of non existant index of array by interpolation.

eg:

arry = [4 5 6];
index = 1.5; 
suchfunction(arry,index) %should return a value between the index 1 and 2 by interpolation (would be 4.5)

ans = 4.5

Could someone help me!?

Answer 1

[Star Strider]

Use the interp1 function:

arry = [4 5 6];
idx  = 1:3;
idxi = 1.5;
arryi = interp1(idx, arry, idxi)

arryi =
     4.5