replace values by the previous value

Hi, I had to change values (below 60) in column 11 to the mean of a colomn 11. This worked (with the function below), but now I need to change values below 60 in colomn 11 to the previous value in column 11. I tried to figure it out by means of previous posts, but I can't make it work. Thanks!

>> lId = data(:,11) <= 60 ; data( data(:,11)<=60, 11 ) = mean(data(:,11));

Answer 1

[Mischa Kim]

Not quite sure if I understand what you are trying to do, but how about

 data = 10*rand(5)

 old  = data(data(:,1)<=6,1)
 data(data(:,1)<=6,1) = mean(data(:,1))

 data(data(:,1)<=6,1) = old

I worked with a smaller size array and other numbers just to demonstrate.

[nanouk verhulst]

Thank you, I clearly did not explain well. What I need to do is to change values below 60 in a certain column to the previous value in that column. So I need to replace = mean(data(:,11)); with a function that can do this. I tried things such as = data (data(:,11)<=60)-1, but I cannot manage to capture the previous value.

[Mischa Kim]

What do you mean by previous? Same column, row above? Let's say you have a matrix

 A = [1  2  3  4;...
      5  6  7  8;...
      9 10 11 12]

and had to replace all values below 10 in column 3.

[nanouk verhulst]

yes row above in same column. In your example it would not be the right value since 3 cannot be changed by the previous value (which should be higher than 10). so if the matrix would be

 A = [9  10  11  12;...
      8   7   6   5;...
      4   3   2   1]

6 would have to become 11 and 2 would have to become 11