MATLAB Answers

Trushit
0

Append rows at the end of Matrix

Asked by Trushit
on 27 Jan 2014
Latest activity Commented on by Hugh
on 19 Sep 2018 at 18:29

Hi,

a = [1 2 3 ; 4 5 6; 7 8 9]; --> 3x3 matrix

I want to insert at the end number of raws with same elements such as [5 5 5] and make the matrix 10 x 3 i.e. I want to insert 7 more raws with [5 5 5]. Please explain.

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2 Answers

Answer by Amit
on 27 Jan 2014

A = [1 2 3;4 5 6;7 8 9];
A = [A; ones(7,3)*5];

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Thank you. It's short and speedy.

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Answer by Azzi Abdelmalek
on 27 Jan 2014
Edited by Azzi Abdelmalek
on 27 Jan 2014

a = [1 2 3 ; 4 5 6; 7 8 9];
b=[5 5 5]  
c=[a;b]% add one row
c=[a;repmat(b,7,1)]  %add 7rows

  3 Comments

Thanks a lot. The answer also helps when we have different elements in stead of all same.

What if I have to insert the row somewhere between middle of the original matrix? Thank you in advance.

Hugh
on 19 Sep 2018 at 18:29

Yes, a long-time-after answer to a long-time-after question, but why not?

a = [1 2 3; 4 5 6; 7 8 9];
b = [5 5 5];
a = [a(1,1:3);b;a(2:3,1:3)]

Or for a bit more malleable solution (variable row to add to):

a = [1 2 3; 4 5 6; 7 8 9];
b = [5 5 5];
addrow = 2;
a = [a(1:addrow-1,1:3);b;a(addrow:3,1:3)]

Or a bit prettier, and even more malleable (if a has variable number of rows):

a = [1 2 3; 4 5 6; 7 8 9];
b = [5 5 5];
addrow = 2;
a = [a(1:addrow-1,:);b;a(addrow:end,:)]

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