poster
2019-12-10, 20:41
因此，我有一个1xN个不同长度向量的单元格数组。我想将它们附加到矩阵中，以便可以使用imagesc显示它们。显然，矩阵必须是最大向量的宽度。我当前的代码如下：
tcell = {[1,2,3], [1,2,3,4,5], [1,2,3,4,5,6], [1], []}; lens = cellfun('length', tcell); rmat = NaN(length(tcell), max(lens)); for i = 1:length(tcell) rmat(i, 1:lens(i)) = tcell{i}; end 有人知道这种问题的矢量化解决方案吗？由于MATLAB的JIT，我并不真正担心此循环的速度。我只是想扩展自己的知识，这是我在编程中经常遇到的一个案例。
回答：
这是一个使用带有匿名函数的 (https://www.mathworks.com/help/matlab/matlab_prog/anonymous-functions.html) cellfun (https://www.mathworks.com/help/matlab/ref/cellfun.html)的解决方案，首先用NaN (https://www.mathworks.com/help/matlab/ref/nan.html)值填充每个单元格，然后使用vertcat (https://www.mathworks.com/help/matlab/ref/vertcat.html)将单元格内容放入矩阵中：
tcell = {[1 2 3], [1 2 3 4 5], [1 2 3 4 5 6], [1], []}; % Sample cell array maxSize = max(cellfun(@numel, tcell)); % Get the maximum vector size fcn = @(x) [x nan(1, maxSize-numel(x))]; % Create an anonymous function rmat = cellfun(fcn, tcell, 'UniformOutput', false); % Pad each cell with NaNs rmat = vertcat(rmat{:}); % Vertically concatenate cells 并输出：
rmat = 1 2 3 NaN NaN NaN 1 2 3 4 5 NaN 1 2 3 4 5 6 1 NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
更多&回答... (https://stackoverflow.com/questions/3054437)
tcell = {[1,2,3], [1,2,3,4,5], [1,2,3,4,5,6], [1], []}; lens = cellfun('length', tcell); rmat = NaN(length(tcell), max(lens)); for i = 1:length(tcell) rmat(i, 1:lens(i)) = tcell{i}; end 有人知道这种问题的矢量化解决方案吗？由于MATLAB的JIT，我并不真正担心此循环的速度。我只是想扩展自己的知识，这是我在编程中经常遇到的一个案例。
回答：
这是一个使用带有匿名函数的 (https://www.mathworks.com/help/matlab/matlab_prog/anonymous-functions.html) cellfun (https://www.mathworks.com/help/matlab/ref/cellfun.html)的解决方案，首先用NaN (https://www.mathworks.com/help/matlab/ref/nan.html)值填充每个单元格，然后使用vertcat (https://www.mathworks.com/help/matlab/ref/vertcat.html)将单元格内容放入矩阵中：
tcell = {[1 2 3], [1 2 3 4 5], [1 2 3 4 5 6], [1], []}; % Sample cell array maxSize = max(cellfun(@numel, tcell)); % Get the maximum vector size fcn = @(x) [x nan(1, maxSize-numel(x))]; % Create an anonymous function rmat = cellfun(fcn, tcell, 'UniformOutput', false); % Pad each cell with NaNs rmat = vertcat(rmat{:}); % Vertically concatenate cells 并输出：
rmat = 1 2 3 NaN NaN NaN 1 2 3 4 5 NaN 1 2 3 4 5 6 1 NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
更多&回答... (https://stackoverflow.com/questions/3054437)