arrays - 从数组中提取一定数量的 block

Question

我有一个向量，我想从中提取所有 4:

x = [1 1 1 4 4 5 5 4 6 1 2 4 4 4 9 8 4 4 4 4]

这样我将得到 4 个向量或一个包含 4 的 4 个 block 的单元格:

[4 4], [4], [4 4 4], [4 4 4 4]

谢谢!

Answer 1

您可以使用 arrayfun 从适当的范围创建单元格:

x = [1 1 1 4 4 5 5 4 6 1 2 4 4 4 9 8 4 4 4 4];     
x = [0, x, 0]; D = diff (x==4);               % pad array and diff its mask
A = find (D == 1); B = find (D == -1);        % find inflection points
out = arrayfun (@ (a,b) {x(a+1 : b)}, A, B)   % collect ranges in cells