matlab - 一次设置多个字段/将新字段添加到单元格结构

Question

我有一个 1xn 结构。这些结构包含一些带有数字单元格的字段。并非每个结构都具有相同的字段。所以我想将缺少的字段添加到结构中。但是我没听懂。

%  Mimimal example
%  I have same cells, imported from csv by csv2cell()

clear

dataCell{1}={"field_a","field_b","field_c"; ...
    1,2,3; ...
    4,5,6};

dataCell{2}={"field_a","field_b","field_d"; ...
    1,2,4; ...
    4,5,8};

%   Then I convert them to a struct
for ii=1:numel(dataCell)    
DataStruct{ii}=cell2struct((dataCell{ii}(2:end,:)),[dataCell{ii}(1,:)],2);
  try fields=[fields, fieldnames(DataStruct{ii})']; % fails for the first loop, because 'fields' doesn't exist yet
  catch
   fields=[fieldnames(DataStruct{ii})']; % create 'fields' in the first loop
  end
end

% Create a list of all existing fields
fields=unique(fields);

% Now look for the missing fields and add them to the struct
for jj=1:numel(DataStruct)
  missing_fields{jj} = setdiff(fields,fieldnames(DataStruct{jj}));
  for kk=1:numel(missing_fields)
    DataStruct{jj}.(missing_fields{jj}{kk})=NaN*zeros(numel(dataCell{jj}(2:end,1)),1); % Execution fails here!
  end
end

这会导致错误:

Octave 误差

error: invalid assignment to cs-list outside multiple assignment
error: called from:
error:   ~/example.m at line 29, column 44

Matlab 错误

Insufficient outputs from right hand side to satisfy comma separated
list expansion on left hand side.  Missing [] are the most likely cause.

问题是，DataStruct{1}.field_a 的输出不是矩阵或单元格，而是多个 ans。是否可以轻松地将单元格转换为矩阵或导入 csv 的更好可能性？

另一种可能是这样的

 DataStruct{jj}=setfields(missing_fields{jj},NaN_Values{jj})

其中 missing_fields{jj} 和 NaN_Values 都是长度相同的单元格，因此我可以一次设置多个字段。

Answer 1

您使用 deal 函数将输出分配给输入。对于您的示例:

% Now look for the missing fields and add them to the struct
for jj=1:numel(DataStruct)
  missing_fields{jj} = setdiff(fields,fieldnames(DataStruct{jj}));
  for kk=1:numel(missing_fields)
    [DataStruct{jj}.(missing_fields{jj}{kk})] = deal(NaN*zeros(numel(dataCell{jj}(2:end,1)),1));
  end
end

请注意，您将得到一个Index exceeds matrix dimensions，但这是由于不同的问题 - 我相信您能够解决这个问题!