# Convert cell array to matrix with two columns and sort rows by first column value

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Nik Rocky on 10 Feb 2021
Commented: Nik Rocky on 10 Feb 2021
Hello,
I have a large Cell array with multiple cells. Every these cells has n-rows and two columns.
I want to convert this cell-array to one large matrix with j x 2 double matrix (j is sum value of all rows of all cells)
Cell_x =
1×8 cell array
Columns 1 through 4
{13×2 double} {10×2 double} {9×2 double} {11×2 double}
Columns 5 through 8
{9×2 double} {12×2 double} {6×2 double} {7×2 double}
Matrix_x =
77 x 2 double
after it, I want to sort the rows by values of the first column:
Test_unsorted =
4 45
8 78
9 77
1 68
Test_sorted =
1 68
4 45
8 78
9 77

Stephen Cobeldick on 10 Feb 2021
Edited: Stephen Cobeldick on 10 Feb 2021
More robust and more efficient than using cell2mat:
M = vertcat(Cell_x{:});
M = sortrows(M,1)
Nik Rocky on 10 Feb 2021
Thank you, I get the same answer by myself and was writing a solution here =)

the cyclist on 10 Feb 2021
Edited: the cyclist on 10 Feb 2021
I think this does what you want:
% Set RNG seed, for repeatability
rng default
% Make up some data
Cell_x = {rand(13,2),rand(7,2)};
% Convert cell to matrix, and sort rows by first column
sortrows(cell2mat(Cell_x'),1)
ans = 20×2
0.0318 0.9502 0.0975 0.7922 0.1270 0.1419 0.1576 0.9340 0.1712 0.6948 0.2769 0.0344 0.2785 0.9595 0.3922 0.0971 0.5469 0.6557 0.6324 0.9157
Nik Rocky on 10 Feb 2021
Also, nice solution, thank you!