matlab - 具有/不同列数的 vec2mat

Question

引用Reshape row wise w/ different starting/ending elements number @Divakar 提供了一个很好的解决方案，但是，如果列数不总是相同怎么办？

样本运行 -

>> A'
ans =
     4     9     8     9     6     1     8     9     7     7     7     4     6     2     7     1
>> out
out =
     4     9     8     9     0     0
     6     1     8     9     7     7
     7     4     6     2     7     1

我只取了 A 的前 4 项并将它们放入，然后用 0 填充其余 2 个空单元格。所以 ncols = [4 6 6]。不幸的是 vet2mat 不允许向量作为列号。

有什么建议吗？

Answer 1

您可以雇用 bsxfun此处的屏蔽功能 -

%// Random inputs
A = randi(9,1,15)
ncols = [4 6 5]

%// Initialize output arary of transposed size as compared to the desired 
%// output arary size, as we need to insert values into it row-wise and MATLAB 
%// follows column-major indexing
out = zeros(max(ncols),numel(ncols)); 

mask =  bsxfun(@le,[1:max(ncols)]',ncols); %//'# valid positions mask for output
out(mask) = A; %// insert input array elements
out = out.' %//'# transpose output back to the desired output array size

代码运行-

A =
     5     3     7     2     7     2     4     6     8     1     9     7     5     4     5
ncols =
     4     6     5
out =
     5     3     7     2     0     0
     7     2     4     6     8     1
     9     7     5     4     5     0