convert a cell (Rx1 cell) to a vector (Rx1 double)

Question

Alberto Acri 2023-12-7

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2057719-convert-a-cell-rx1-cell-to-a-vector-rx1-double

编辑： Stephen23 2023-12-8

rows_check_n.mat

Hi. I want to convert the cell 'rows_check_n' into a vector of type double with the numbers inside the cell.

I tried 'cell2mat' but it is not clear to me why it transforms 270x1 cell into a vector 257x1 double. How can I solve this?

rows_check_n = load("rows_check_n.mat");
rows_check_n = rows_check_n.rows_check_n;   % 270x1 cell
    
rows_check_n_double = cell2mat(rows_check_n);  % 257x1 double

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Answer 1

Walter Roberson 2023-12-7

1
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https://ww2.mathworks.cn/matlabcentral/answers/2057719-convert-a-cell-rx1-cell-to-a-vector-rx1-double#answer_1367604

移动：Walter Roberson 2023-12-7

在 MATLAB Online 中打开

rows_check_n.mat

13 entries in the cell are empty.

rows_check_n = load("rows_check_n.mat");
rows_check_n = rows_check_n.rows_check_n;   % 270x1 cell
disp(find(cellfun(@isempty, rows_check_n)))
    99
   100
   101
   102
   103
   104
   105
   106
   107
   108
   109
   110
   111

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Answer 2

Stephen23 2023-12-8

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2057719-convert-a-cell-rx1-cell-to-a-vector-rx1-double#answer_1367714

编辑：Stephen23 2023-12-8

在 MATLAB Online 中打开

rows_check_n.mat

"but it is not clear to me why it transforms 270x1 cell into a vector 257x1 double"

It is easy to check your data (you have been using MATLAB for over three years now, you can do this too):

S = load("rows_check_n.mat");
C = S.rows_check_n   % 270x1 cell
C = 270×1 cell array
    {[106798]}
    {[106799]}
    {[106800]}
    {[106801]}
    {[106802]}
    {[106803]}
    {[107309]}
    {[107310]}
    {[107311]}
    {[107312]}
    {[107313]}
    {[107314]}
    {[107315]}
    {[107820]}
    {[107821]}
    {[107822]}
X = cellfun(@isscalar,C);
all(X) % are all of them scalar as you believe? (hint: no)
ans = logical
   0

Lets replace the non-scalar elements of C with NaNs, then you get a vector of the same size as C:

V = nan(size(C));
V(X) = [C{X}]
V = 270×1
      106798
      106799
      106800
      106801
      106802
      106803
      107309
      107310
      107311
      107312