resample data based on a particular variable

I have a large dataset as below. From the data, I want to randomly sample based on 'id' produce the same size data. Since the data has 5 ids, I would like to sample 5 ids with replacement and produce a dataset.

id  value  var1  var2  …
1  1      
1  2      
1  3      
1  4      
2  5      
2  6      
2  7      
3  8      
3  9      
3  10      
4  11      
4  12      
4  13      
5  14      
5  15      
5  16

With the data, the desired output could be as below (because I want to sample ids with replacement, there could be duplicated ids)

id  value  var1  var2  …
2  5      
2  6      
2  7      
4  11      
4  12      
4  13      
3  8      
3  9      
3  10      
2  5      
2  6      
2  7      
1  1      
1  2      
1  3      
1  4

[KSSV]

What is the difference between both the datasets? They are same.......in the second one you have repeated id 2.

[Boram Lim]

I want to randomly resample data based on id variable

Answer 1

[KSSV]

A = [1  1      
1  2      
1  3      
1  4      
2  5      
2  6      
2  7      
3  8      
3  9      
3  10      
4  11      
4  12      
4  13      
5  14      
5  15      
5  16  ];

id = A(:,1) ; val = A(:,2) ;

N = max(id) ;

idx = randperm(N) ;

iwant = cell(N,1) ;
for i = 1:N
    iwant{i} = A(id==idx(i),:) ;
end
iwant = cell2mat(iwant)

[Boram Lim]

Thank you for your comment. However, any simple way without using for-loop? my data size is around 10million and this work should be done several times.