# convert matrix in single column

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Gaetano Sciacovelli on 18 Apr 2012
Edited: Image Analyst on 14 Jul 2022
Hi, I have to convert a matrix in one column vector composed of all the columns of the original matrix. How can I do this? Thanks
Image Analyst on 9 Apr 2020
You said "I have to convert a matrix in one column vector composed of all the columns of the original matrix." I thought you meant you had a column vector and had to convert it to a matrix having the same number of columns as the original matrix from where the column vector came. In other words, I thought you meant "I have to convert a matrix of one column vector INTO ONE composed of all the columns of the original matrix."
Seeing the answer you accepted, it appears that you actually meant "I have to convert a matrix INTO a one column vector that is composed of all the columns of the original matrix." Leaving out seemingly minor words completely changes the interpretation of the question, as does their placement in the sentence.

Andrei Bobrov on 18 Apr 2012
yourvector = yourmatrix(:);
Image Analyst on 14 Jul 2022
Edited: Image Analyst on 14 Jul 2022
@rishika yadav you can use interp2 to interpolate a different height:
m = reshape(1:18, [], 3) % Create 6 row by 3 column sample data
[oldHeight, columns] = size(m)
% Make the matrix taller by interpolating.
newHeight = 8;
[xq,yq] = meshgrid(1:columns, linspace(1, oldHeight, newHeight));
mTaller = interp2(m, xq, yq)
fprintf('The size of mTaller is %d rows by %d columns.\n\n', size(mTaller, 1), size(mTaller, 2))
% Make the matrix taller by interpolating.
newHeight = 3;
[xq,yq] = meshgrid(1:columns, linspace(1, oldHeight, newHeight));
mShorter = interp2(m, xq, yq)
fprintf('The size of mShorter is %d rows by %d columns.\n', size(mShorter, 1), size(mShorter, 2))
The first/top and last/bottom rows will have the same values, and more, or fewer, rows will be interpolated in between the top row and bottom row so that you have your new desired height.

### More Answers (4)

Image Analyst on 18 Apr 2012
If your column vector was "composed of all the columns of the original matrix", then use the reshape() command to turn it from a column vector back into the original 2D matrix.
matrix2D = reshape(columnVector, [rows columns]);
(The converse, how to get the column vector in the first place (what you may have done to get your vector) is accomplished like this columnVector = fullMatrix(:).)
James Tursa on 25 Oct 2019
Please post a new Question with the details of your problem.

Kyril Kaufmann on 26 Apr 2020
For a more algorithmic solution:
% From matrix to vector
N = 10;
mat1 = rand(N);
vec1 = zeros(N*N,1);
for i=1:N
for j=1:N
vec1((i-1)*N + j) = mat1(i,j);
end
end
% From vector to matrix
N = 10;
vec2 = rand(N*N,1);
mat2 = zeros(N);
for i=1:N
for j=1:N
mat2(i,j) = vec2((i-1)*N + j);
end
end

Rifat Hossain on 15 Dec 2016
columnvector=matrix(:) this work fine

AMIR KHFAGI on 23 Mar 2020
Hi, I have to convert one column vector to a matrix in matlab. How can I do this?
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Shuyun Yuan on 7 Apr 2020
reshape function