Generating sets of non repeating random numbers

Hi,

How do I create 10 sets of random numbers within a range such that after every set, the numbers previously generated can’t be repeated or generated again i.e if I generate [1,3,8,6] from the range [1:40] those numbers would be deleted from the range and can’t be generated again

Answer 1

[dpb]

>> ix=reshape(randperm(40),10,[])
ix =
    35    23    21    40
    26    17     8    36
    38     5    27    18
    20    10    11     9
    30    33    24    28
    16    25    34    15
     3    12    32     7
    19    37    14    13
    31     4     1     2
    29    39     6    22
>>

Answer 2

[Anton Semechko]

Here is an example:

S=reshape(randperm(40),[],4);

All elements in S will be in the range [1 40] and unique. From this it follows that all 10 rows of S will also be unique.

[Toluwani Adekunle]

Thanks, I have another question, what if the range of numbers I’m selecting from isn’t the same as the amount of sets I want to generate, i.e the range is 300 let’s say and I want a 27 by 9 matrix or the range is unknown

[Anton Semechko]

Same idea applies, but cutoff the extraneous samples before reshaping. Example for 300 range and 27-by-9 matrix.

S=radndperm(300);
S=S(1:(27*9));
S=reshape(S,27,9);