Indices of 2D array

I have a 1D (very big one) array like below:

data =[ 2 5 0 15 12 7 4 8 19 14 20 25 18 13 40 ];

I want to make the lowest value to zero in every 3 element. I firstly reshaped it to be like:

reshaped_data =

2 15 4 14 18

5 12 8 20 13

0 7 19 25 40

And then sorted each column and now I have the indices of the sorted data as below.

sorted_data_index =

2 1 3 3 3

1 2 2 2 1

3 3 1 1 2

So, please let me know how can I use sorted_data_index as indices of reshaped_data to be able to make the lowest values zero?

I can do this within a for loop, but it would be very slow.

Thanks

Answer 1

[Sindar]

data =[ 2     5     0    15    12     7     4     8    19    14    20    25    18    13    40 ];
reshaped_data = reshape(data,3,[]);
[~,idx]=sort(reshaped_data,1,'descend');
reshaped_data( sub2ind( size(reshaped_data), idx(3,:), 1:size(reshaped_data,2)) ) = 0
reshaped_data =
     2    15     0     0    18
     5    12     8    20     0
     0     0    19    25    40

[Mohammad Torabi]

Thanks for your help

Answer 2

[Luna]

try this:

data =[ 2     5     0    15    12     7     4     8    19    14    20    25    18    13    40 ];
reshaped_data = reshape(data,3,length(data)/3);
[min_vals,idx] = min(reshaped_data);
idx_increment = 0:3:length(data)-3;
element_number_in_matrix = idx + idx_increment;
reshaped_data(element_number_in_matrix) = 0;
new_data = reshape(reshaped_data,1,length(data));

[Mohammad Torabi]

Thanks for your help