修改结构体数组并返回结构体数组

Question

我有一个结构体数组：一个 1x10 结构体数组，其中包含以下字段：N、t、q、r、T，每个字段都是double 类型的向量。

10 个数组条目分别代表实验中测试条件的结果。我希望能够制作一个函数，它采用两个索引index1 和index2，并修改组成的 N、t、q、r 向量（T 是单个数字），使它们变成长度 index1 :index2。像

function sa = modifier(struct_array, index1, index2)
    sa = structfun(@(x) x(index1:index2), struct_array, 'UniformOutput', false)
    stuff
end

现在，stuff 所在的位置，我尝试使用 structfun 和 cellfun，请参阅 here，除了它们分别返回一个结构体和一个元胞数组，而我需要返回一个 结构数组。

这样做的目的是为了能够得到某些部分的实验结果，例如也许每个单元格内每个向量中的前五个条目对应于实验的初始周期。

请让我知道这是否可行，以及我将如何去做！

Answer 1

你可以试试这个：

从这个问题的answer，我想出了如何循环遍历结构字段。我修改了代码来解决您的问题，方法是从通过 for 循环的每个字段中提取子样本，然后将该数据的所需子集复制到具有相同名称字段的新结构数组中。

% Define indexes for extraction
fieldsToTrim = {'a' 'b'};
idx = 2:3; % Create index vector for extracting selected data range

% Define test struct to be read
teststruct.a = [1 2 3];
teststruct.b = [4 5 6];
teststruct.c = [7 8 9];

% Get names of struct fields
fields = fieldnames(teststruct);

% Loop through each field and extract the subset
for i = 1:numel(fields)
    if max(strcmp(fields{i},fieldsToTrim)) > 0
        % If current matches one of the fields selected for extraction
        % extract subset
        teststructResults.(fields{i}) = teststruct.(fields{i})(idx);
    else
        % Else, copy all contents on field to resulting struct
        teststructResults.(fields{i}) = teststruct.(fields{i});
    end
end

最后要将this变成一个函数，可以将上面的代码修改成这样：

function teststructResults =  extractSubsetFromStruct(teststruct,fieldsToTrim,idx1, idx2)
    % idx1 and idx2 are the start and end indicies of the desired range

    % fieldsToTrim is a string array of the field names you want
    % included in the trimming, all other fields will be fully copied

    % teststruct is your input structure which you are extracting the
    % subset from

    % teststructResults is the output containing identically named
    % struct fields to the input, but only containing data from the selected range

    idx = idx1:idx2; % Create index vector for extracting selected data range

    % Get names of struct fields
    fields = fieldnames(teststruct);

    % Loop through each field and extract the subset
    for i = 1:numel(fields) 
        if max(strcmp(fields{i},fieldsToTrim)) > 0
            % If current matches one of the fields selected for extraction
            % extract subset
            temp = teststruct.(fields{i});
            teststructResults.(fields{i}) = temp(idx);
        else
            % Else, copy all contents on field to resulting struct
            teststructResults.(fields{i}) = teststruct.(fields{i});
        end
    end
end

我成功运行了这样的函数：

teststruct = 

    a: [1 2 3]
    b: [4 5 6]
    c: [7 8 9]

>> extractSubsetFromStruct(teststruct,{'a' 'b'},2,3)

ans = 

    a: [2 3]
    b: [5 6]
    c: [7 8 9]