MatLab 相对于第 1 列转换矩阵

Question

这个问题是MatLab (or any other language) to convert a matrix or a csv to put 2nd column values to the same row if 1st column value is the same? 和Group values in different rows by their first-column index 的产物

如果

      A = [2 3 234 ; 2 44 99999; 2 99999 99999; 3 123 99; 3 1232 45; 5 99999 57]

1st column |  2nd column | 3rd column
--------------------------------------
2             3          234
2             44         99999
2             99999      99999
3             123        99
3             1232       45
5             99999        57

我想做

1st col |  2nd col | 3rd col | 4th col | 5th col | 6th col| 7th col
--------------------------------------------------------------------
2         3        234       44       
3         123      99        1232      45
5         57

也就是说，对于 A 的第 1 列中的每个数字，我想输入除“99999”之外的数字

如果我们忽略“99999除外”部分，我们可以编码为Group values in different rows by their first-column index

[U, ix, iu] = unique(A(:,1));
vals = reshape(A(:, 2:end).', [], 1);                    %'// Columnize values
subs = reshape(iu(:, ones(size(A, 2) - 1, 1)).', [], 1); %'// Replicate indices
r = accumarray(subs, vals, [], @(x){x'});

但显然这段代码不会忽略 99999。

我想有两种方法

1. first make r, and then remove 99999
2. remove 99999 first, and then make r

不管怎样，我只想要更快的。

提前谢谢你！

Answer 1

我认为选项 1 更好，即先制作 r，然后删除 99999。有了 r，你可以删除 99999，如下所示：

r2 = {}; % new cell array without 99999

for i = 1:numel(r)    
    rCell = r{i};
    whereIs9999 = rCell == 99999; 
    rCell(whereIs9999) = []; % remove 99999
    r2{i} = rCell;
end

或者更花哨的方式：

r2= cellfun(@(c) {c(c~=99999)}, r);