在Matlab/Octave中从向量中识别(和移除)序列

Question

我试图从Matlab(或Octave)中的数字向量中修剪任何长度为3或更长的序列.例如,给定的矢量数据集,

dataSet = [1 2 3 7 9 11 13 17 18 19 20 22 24 25 26 28 30 31];

删除长度为3或更长的所有序列将产生prunedDataSet:

prunedDataSet = [7 9 11 13 22 28 30 31 ];

我可以强制解决方案,但我怀疑使用向量/矩阵操作有一种更简洁(也许是有效)的方法,但我总是对某些东西产生索引或所述索引的值感到困惑.建议？

这是我提出的蛮力方法:

dataSet = [1 2 3 7 9 11 13 17 18 19 20 22 24 25 26 28 30 31];
benign = [];
for i = 1:size(dataSet,2)-2;
    if (dataSet(i) == (dataSet(i+1)-1) && dataSet(i) == dataSet(i+2)-2);
        benign = [benign i ] ;
    end;
end;

remove = [];
for i = 1:size(benign,2);
    remove = [remove benign(i) benign(i)+1 benign(i)+2 ];
end;

remove = unique(remove);

prunedDataSet = setdiff(dataSet, dataSet(remove));

Answer 1

这是使用DIFF和STRFIND的解决方案

%# define dataset
dataSet = [1 2 3 7 9 11 13 17 18 19 20 22 24 25 26 28 30 31];

%# take the difference. Whatever is part of a sequence will have difference 1
dds = diff(dataSet);

%# sequences of 3 lead to two consecutive ones. Sequences of 4 are like two sequences of 3
seqIdx = findstr(dds,[1 1]);

%# remove start, start+1, start+2
dataSet(bsxfun(@plus,seqIdx,[0;1;2])) = []
dataSet =

     7     9    11    13    22    28    30    31