How do I erase following data?

I want to erase following data when data goes down under 28.

For example,

If I have this matrix

36   33   31   29   30    27    31    33    24,

I want to make the matrix into

36   33   31   29   30  NaN NaN NaN NaN.

--> when I first met a number under 28, following datas are erased like this.

Thanks.

Answer 1

[Walter Roberson]

x(find(x<28,1):end) = nan ;

or

x(~cumprod(x>=28)) = nan;

[Mehmed Saad]

oops i posted the same answer without looking

[HyoJae Lee]

Thanks for helping.

This is the one that I want to find.

Appreciated!

Answer 2

[Mehmed Saad]

you can use find but not recommended

x = [36   33   31   29   30    27    31    33    24];
x(find(x<28,1):end) = nan

x =

36 33 31 29 30 NaN NaN NaN NaN

[HyoJae Lee]

Thanks for help!