Set 'n' value by making matlab automatically calculate from a matrix

I have a matrix of XXXXXx1 and i want matlab to automtically calculate an even division of it and set it as a new value.

eg: i have a matrix of 10000x1 and i want matlab to divide it by a fixed number (eg 400) and give me the return value of n=25.

[Rik]

You mean like this?

n=size(A,1)/fixed;

[Hunyum Murya]

that is not giving me the value i want. its just dividing y/fixed value and giving me that output.

[Jan]

I do not understand the question. Please clarify it.

[Rik]

If A contains your vector of size 10000x1 and fixed is 400, then my line of code results in n being set to 25. If that is not what you mean, you should describe what it is you mean, preferably showing the code you tried.

[Image Analyst]

Do you want to take 25 subsamples of the original vector? Again, please clarify.