in a loop like go back

Hello! Now I use this loop

for i=1:length(data) 
    if a(i)<=1
       a(i)=a(i-1)    
    end
end

but I was faced with the calculation that the zones of zero values ​​and they give me the wrong result

 a(i)=a(i-1)   % find(a)

what’s the best way to write, not a (i-1), but write a (i up to the first value that meets the if condition)

Answer 1

[Matt J]

first=find(a<=1, 1);

a(1:first)