问题
如何用字符串（最常出现的类别）和数字列的平均值来替换缺失的列值？
数据示例来自于：
例如，用‘Iris-setosa’替换NaN
我有的代码
它只能替换数值，但如何替换字符串呢？
function dataWithReplaced = replaceNaNWithAvg(data)dataWithReplaced = [ ];averagePerCol = table2array(varfun(@nanmean, data(: , 1:4)));for i = 1:4 dataColumn = table2array(data( : , i)); dataColumn(isnan(dataColumn)) = averagePerCol(1, i); dataWithReplaced = [dataWithReplaced dataColumn];endend我是MATLAB的新手，所以很多事情对我来说并不明显。
回答：
以下解决方案解决了这个问题：
- 将表格的最后一列转换为单元数组（单元数组用于保存长度不同的字符串）。
- 从单元数组中删除所有NaN元素（NaN元素会干扰后续部分）。
- 在单元数组中查找最常重复的字符串。
- 查找stringColumn中所有NaN元素的索引（我使用了基于前一部分的
cellfun）。 - 用最常见的字符串替换找到的索引中的元素。
由于你是MATLAB的新手，我的解决方案看起来可能会对你来说非常复杂（对我来说也看起来很复杂）。
可能有更简单的解决方案，但我找不到…
请看以下代码示例：
%创建示例数据表。%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%VarName1 = [4.9; 7.3; 6.7; 7.2; 6.5; 6.4; 6.8; 5.7; 5.8; 6.4; 6.5];VarName2 = [2.5; 2.9; 2.5; 3.6; 3.2; 2.7; 3.0; 2.5; 2.8; 3.2; 3.0];VarName3 = [4.5; 6.3; 5.8; 6.1; 5.1; 5.3; 5.5; 5.0; 5.1; 5.3; 5.5];VarName4 = [1.7; 1.8; 1.8; 2.5; 2.0; 1.9; 2.1; 2.0; 2.4; 2.3; 1.8];VarName5 = {NaN; 'aa'; 'aa'; 'bbb'; NaN; 'ccc'; 'ccc'; 'ccc'; 'ccc'; 'dddd'; 'dddd'};data = table(VarName1, VarName2, VarName3, VarName4, VarName5);%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%将表格的最后一列转换为单元数组。stringColumn = table2cell(data(:, 5));%从单元数组中删除所有NaN元素%参考： https://www.mathworks.com/matlabcentral/newsreader/view_thread/314852x = stringColumn(cell2mat(cellfun(@ischar,stringColumn,'UniformOutput',0)));%在单元数组中查找最常重复的字符串：%参考： https://www.mathworks.com/matlabcentral/answers/7973-how-to-find-out-which-item-is-mode-of-cell-array%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%y = unique(x);n = zeros(length(y), 1);for iy = 1:length(y) n(iy) = length(find(strcmp(y{iy}, x)));end[~, itemp] = max(n);commonStr = y(itemp);%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%查找stringColumn中所有NaN元素的索引。nanIdx = find(cell2mat(cellfun(@ischar,stringColumn,'UniformOutput',0)) == 0);%用commonStr替换NaN值的元素。stringColumn(nanIdx) = commonStr;%替换原始表的最后一列data(:, 5) = stringColumn;