How to convert row to matrix with below format????

Asked by Yuvaraj V on 6 Jun 2018

Latest activity Commented on by Yuvaraj V on 6 Jun 2018

Accepted Answer by Stephen Cobeldick

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I need to convert row to matrix. For example, A=[1 2 3 4 5]

Need answer like this, Ans=[1 0 0 0 0; 0 1 0 0 0; 0 0 1 0 0; 0 0 0 1 0; 0 0 0 0 1]

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Yuvaraj V on 6 Jun 2018

@Stephen Cobeldick: yes. your answer is working. Thank you.

Also, I have doubt from your question.

If input A=[5,1,1,4], the output like this,

0 0 0 0 1

1 0 0 0 0

0 0 0 1 0

Help me sir.

Stephen Cobeldick on 6 Jun 2018

@Yuvaraj V: I have updated my answer to match your comment.

Yuvaraj V on 6 Jun 2018

@Stephen Cobeldick: Thank You so much

2 Answers

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Answer by Stephen Cobeldick on 6 Jun 2018

Edited by Stephen Cobeldick on 6 Jun 2018

Accepted Answer

>> A = [3,1,1,4];
>> N = numel(A);
>> Z = zeros(N);
>> Z(sub2ind([N,N],1:N,A)) = 1
Z =
   0   0   1   0
   1   0   0   0
   1   0   0   0
   0   0   0   1

EDIT: if my example is acceptable, as you now write, then you will need something like this:

>> A = [5,1,1,4];
>> R = numel(A);
>> C = max(A);
>> Z = zeros(R,C);
>> Z(sub2ind([R,C],1:R,A)) = 1
Z =
   0   0   0   0   1
   1   0   0   0   0
   1   0   0   0   0
   0   0   0   1   0

1 Comment

Yuvaraj V on 6 Jun 2018

@Stephen Cobeldick: Thank You so much

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Answer by Birdman on 6 Jun 2018

Edited by Birdman on 6 Jun 2018

Something like this should work:

A=[3 1 1 4];
Ans=zeros(max(size(A)));
r=1:max(size(A));
c=A;
idx=sub2ind(size(repmat(A,max(size(A)),1)),r,c);
Ans(idx)=1

2 Comments

Stephen Cobeldick on 6 Jun 2018

@Birdman: there is a syntax error on this line:

Ans=zeros(max(size(A));

Birdman on 6 Jun 2018

Yes there should be one more parenthesis. Thanks.

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Yuvaraj V (view profile)