Do you want to find elements in iris(:,1) (the first column) that are same as iris(1,1)? If so, the following code can:
load iris.dat
j = 1;
for i=1:size(iris,1)-1
if ( iris(i,1)==iris(1,1) )
idx(j) = i; % store the row# which has the same element with iris(1,1)
j = j+1;
end
end
I do not recommend you to make a code which includes the variable that increases the size of the variable dynamically because it takes much more time than creating a variable in one time like:
find(iris(:,1) == iris(1,1))
