Groupsummary on timetable with cell/matrix data

Question

Gregory Bolard 2021-2-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/753604-groupsummary-on-timetable-with-cell-matrix-data

评论： Gregory Bolard 2021-2-23

采纳的回答： dpb

Hello,

Is it possible with groupsummary to apply aggregation function to cell or matrix data?

For example, if I want to average the "Matrix" every 1s with the following timetable example:

    t        Angle        Matrix    
    ________    _____    ______________
2 sec     180.4    {53×53 double}
4 sec     180.4    {53×53 double}
6 sec     180.4    {53×53 double}
8 sec     180.4    {53×53 double}
sec       180.4    {53×53 double}
2 sec     180.4    {53×53 double}
4 sec     180.4    {53×53 double}
6 sec     180.4    {53×53 double}
8 sec     180.4    {53×53 double}

Thank you

Gregory

4 个评论
显示 2更早的评论隐藏 2更早的评论

Image Analyst 2021-2-23

I don't see how groupsummary() applies. Which column is your group? It looks like every row in your table is a distinct group. For simplicity I'd just do (untested)

for k = 1 : size(yourTable, 1)
    thisMatrix = table{k, 3};
    means(k) = mean(thisMatrix(:));
end

dpb 2021-2-23

编辑：dpb 2021-2-23

It's the accumulation mode over minutes I think OP wants, IA. See below for what I think is intended.

I had to go dig in the doc meself; I didn't recall that facility being built into it.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

dpb 2021-2-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/753604-groupsummary-on-timetable-with-cell-matrix-data#answer_631304

编辑：dpb 2021-2-23

Took a little head-scratching, but the following appears to work as desired--

fnMN3=@(c){mean(cat(3,c{:}),3)};        % function to catenate 2D cell array to 3D array, take mean
means=groupsummary(T,'t','minute',fnMN3,'Matrix');

with a sample table here

>> groupsummary(T,'t','minute',fnMN3,'M');
ans =
  1×3 table
       minute_t        GroupCount       fun1_M   
    _______________    __________    ____________
    [0 sec, 60 sec]        6         {5×5 double}
>>

that matched for a set of random integers had created to make a dummy table.

t=seconds(0:0.2:1);
M=randi(100,5,5,numel(t));
T=[array2table(t.','VariableNames',{'t'}) vertcat(cell2table(M(:),'VariableNames',{'M'}))]
T =
  6×2 table
       t            M      
    _______    ____________
sec    {5×5 double}
2 sec    {5×5 double}
4 sec    {5×5 double}
6 sec    {5×5 double}
8 sec    {5×5 double}
sec    {5×5 double}
>> T.M{:}
ans =
  73    81    86    96
  71    88    18    42
  47    46    65    29
  60    23    68    50
  19    29    37    81
ans =
  20    61    50     4
  49    81    27    55
   3    30    76    23
  63    18    30    38
  11    45     8    30
ans =
  46    51    97     7
  25    16    31    31
   2    59    46    33
  38    22    91    21
  65    15    45    18
ans =
  62    27    84    28
  22    10    58    22
  73    94    65    32
  37    61    50    31
  23    31    19    89
ans =
  77    76    72     2
  33    26    12    22
  29   100    39    73
  67    78    92    68
   3    71    30    52
ans =
  24     5    97    39
  32    45    94    24
  42    77    17    87
  23    35    55    26
  54    24    91    83
>> mean(cat(3,T.M{:}),3)
ans =
5000   50.3333   50.1667   81.0000   29.3333
8333   38.6667   44.3333   40.0000   32.6667
6667   32.6667   67.6667   51.3333   46.1667
6667   48.0000   39.5000   64.3333   39.0000
8333   29.1667   35.8333   38.3333   58.8333
>>