Change length of double data

I have 803385 x 1 data double and i want to change to 7547 x 1, how to change it because the graphs are have same shape and i need to change the lenght

[Steven Lord]

Do you want to take just the first 7547 elements? The last? The middle? Do you want to interpolate? Do you want to take (roughly) every 106th element?

[Iqbal Taufik Irfanda]

i want to make same shape with other length (7547), can i?

[Steven Lord]

Let's say you had a 12 element vector that you wanted to shrink down to a 6 element vector.

x = 1:12

There are may different ways to extract six elements out of x. Some of the possibilities:

x1 = x(1:6)
x2 = x(7:12)
x3 = x(4:9)
x4 = x(1:2:11)
x5 = x(randperm(numel(x), 6))

You can also interpolate.

x6 = interp1(1:numel(x), x, linspace(1, numel(x), 6))

How do you want to make a six element vector out of x?

Answer 1

[KSSV]

Read about interp1.

a = rand(803385,1) ; 
N = length(a) ; 
x = (1:N)' ; 
%
xi = linspace(1,N,7547)' ; 
ai = interp1(x,a,xi) ;