struct for loop syntax difficulty

Not sure what I'm doing wrong with the following loop:

      for p=66:1:95;
      Site(p).Day = Data((Data(:,4) == p),:)
      end

I want Site(p) to contain all data from only the days (in column 4) that I am looking for, which should give a 1x29 struct, but at the moment Site(p) is a 1x95 struct where the first 65 entries are blank ([]). I assume the problem is in the first line, but when I make p the correct size (eg p=1:29) I get an error message about dimension mismatch. Also, if I set another vector, eg n=95-66 and p=1:n, I get the same error message. I can't see what I'm doing wrong.

Answer 1

[Walter Roberson]

Site(p-65).Day = Data((Data(:,4) == p),:)

[Sara]

??? Subscript indices must either be
real positive integers or logicals.

[Sara]

I've got it to work with your solution now. Thanks.