how can i write this statement labels=[1;​1;1;1;1;1;​1;1;1;1;1;​1;1;1;1;1;​1;1;1;1;1;​1;1;1;2;2;​2;2;2;2;2;​2;2;2;2;2;​2;2;2;2;2;​2;2;2;2;2;​2;2;3;3;3;​3;3;3;3;3;​3;3;3;3;3;​3;3;3;3;3;​3;3;3;3;3;​3;]; in compress form?

how to write it in compact form avoiding repetition

Answer 1

[Andrei Bobrov]

labels = kron((1:3)',ones(24,1));

or

labels = reshape(ones(24,1)*(1:3),[],1);

[Sheema Khattak]

can you please make me understand this ?

[Andrei Bobrov]

please read about ones, kron, reshape and repmat.

[Sheema Khattak]

ok ,thanks

Answer 2

[Roger Stafford]

 n = 3;
 r = 24;
 labels = reshape(repmat((1:n),r,1),[],1);

[Sheema Khattak]

can you please make me understand this code?

[Roger Stafford]

Why don't you just try it out? That is probably the best way to understand it. Do 1:n first. Then do repmat((1:n),r,1). Then do the 'reshape' of it.

[Sheema Khattak]

ok ,thanks

[PREMANAND]

Thanks.. Roger Stafford for that new information.

Answer 3

[Matt J]

Using KronProd ( link )

>> labelsKP=KronProd({ones(2400,1), (1:3).'});

you can get even more compression. For comparison,

>> labels = kron((1:3)',ones(2400,1));
>> whos labels labelsKP
  Name             Size            Bytes  Class       Attributes

    labels        7200x1             57600  double                
    labelsKP      7200x1             19660  KronProd