MATLAB:用NaN替换每列的前导零

我有一个3D矩阵叫做 mat

我确实有一个可行的解决办法。但是,它包含两个for循环。我想知道是否有可能矢量化和摆脱循环。实际上, 垫子

下面是我的玩具示例:

% Create test matrix
mat = randi(100,20,5,2);
mat(1:5,1,1) = 0;
mat(1:7,2,1) = 0;
mat(1:3,4,1) = 0;
mat(1:10,5,1) = 0;
mat(1:2,1,2) = 0;
mat(1:3,3,2) = 0;
mat(1:7,4,2) = 0;
mat(1:4,5,2) = 0;

% Find first non-zero element in every column
[~, firstNonZero] = max( mat ~= 0 );

% Replace leading zeros with NaN
% How to vectorize this part???
[nRows, nCols, nPlanes] = size(mat);
for j = 1 : nPlanes

   for i = 1 : nCols

       mat(1:firstNonZero(1, i, j)-1, i, j) = NaN;

   end

end