Splitting a vector into 'on' periods

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CarrotCakeIsYum
CarrotCakeIsYum 2015-9-24
评论： Star Strider 2015-9-28
Hi,
I'm investigating data from a force plate (study of balance in people with movement disorders). I have a raw signal such as:
vector = 1 2 3 4 0 0 0 0 5 6 7 4 7 8 0 0 0 1 2 5 4 0 0 0 0 0 5 6
I need to split this signal into separate vectors that only contain sequences of numbers greater than 0. So the ideal result for the above would be:
vector 1 = 1 2 3 4
vector 2 = 5 6 7 4 7 8
vector 3 = 1 2 5 4
vector 4 = 5 6
I hope the question is clear enough. Any help would be greatly appreciated!

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采纳的回答

Star Strider
Star Strider 2015-9-24
I did my best to make this as robust as possible:
vector = [1 2 3 4 0 0 0 0 5 6 7 4 7 8 0 0 0 1 2 5 4 0 0 0 0 0 5 6];
vec_nz = vector > 0; % Non-Zero Elements
dv = diff([0 vec_nz 0]); % Index Vector
on = find(dv > 0);
off = find(dv < 0);
sections = abs(on-off); % Divide ‘vector’ Here
VectorCell = mat2cell(vector(vec_nz), 1, sections); % Create Cell
VectorCell{:} % Display Results (Can Be Deleted)
ans =
1 2 3 4
ans =
5 6 7 4 7 8
ans =
1 2 5 4
ans =
5 6

更多回答（4 个）

Thorsten
Thorsten 2015-9-24
编辑：Thorsten 2015-9-24
I found a solution here: http://stackoverflow.com/questions/27076618/how-to-split-vector-by-zeros-in-matlab
w = [false v~=0 false]; % "close" v with zeros, and transform to logical
starts = find(w(2:end) & ~w(1:end-1)); % find starts of runs of non-zeros
ends = find(~w(2:end) & w(1:end-1))-1; % find ends of runs of non-zeros
result = arrayfun(@(s,e) v(s:e), starts, ends, 'uniformout', false); % build result
You can also use diff to compute starts and ends indices
starts = find(diff(w) == 1);
ends = find((diff(w) == -1)) - 1;
Stephen23
Stephen23 2015-9-24
编辑：Stephen23 2015-9-24
This is fast and simple using accumarray:
V = [1,2,3,4,0,0,0,0,5,6,7,4,7,8,0,0,0,1,2,5,4,0,0,0,0,0,5,6];
X = V>0;
Y = diff([false,X]);
Z = cumsum(Y(X));
out = accumarray(Z(:),V(X),[],@(n){n})
Jos (10584)
Jos (10584) 2015-9-24
% A one-liner, works when vector only contains values as in the example:
vector = [1 2 3 4 0 0 0 0 5 6 7 4 7 8 0 0 0 1 2 5 4 0 0 0 0 0 5 6] ;
OUT = cellfun(@(x) double(x),strsplit(char(vector),char(0)),'un',0) % cellarray
CarrotCakeIsYum
CarrotCakeIsYum 2015-9-28
Thanks everyone - the advice was brilliant and all is working perfectly.

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