Quick way to sum array elements based on flag in another array?

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Ted
Ted 2015-7-14
评论： Ted 2015-7-15
Say I have 2 arrays: one with "clean" data, and one that tells me which data gets lost, as indicated by zeros. If an element is lost, it should be added to the next observed element. Anybody got a quick one-or-two-liner to come up with the summed array?
Example:
clean = [1 2 3 4 5 6]
lost = [1 0 3 0 0 6]
desired = [1 5 15]

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采纳的回答

Stephen23
Stephen23 2015-7-14
编辑：Stephen23 2015-7-14
Try this:
tmp = (1:numel(lost))-[0,cumsum(lost(1:end-1)==0)];
desired = accumarray(tmp.',clean).'
Tested:
>> clean = [1 2 3 4 5 6];
>> lost = [1 0 3 0 0 6];
>> tmp = (1:numel(lost))-[0,cumsum(lost(1:end-1)==0)];
>> desired = accumarray(tmp.',clean).'
desired =
1 5 15
>> clean = [40 10 50 30 40 10 50 30 40 10 50 30];
>> lost = [40 0 50 30 0 10 0 0 40 10 50 30];
>> tmp = (1:numel(lost))-[0,cumsum(lost(1:end-1)==0)];
>> desired = accumarray(tmp.',clean).'
desired =
40 60 30 50 120 10 50 30

更多回答（2 个）

Andrei Bobrov
Andrei Bobrov 2015-7-14
编辑：Andrei Bobrov 2015-7-14
desired = flip(accumarray(cumsum(lost(end:-1:1)~=0)',clean(end:-1:1)),1)';
or
desired = accumarray(cumsum(xor([0,diff(lost > 0)],lost))',clean)';
  2 个评论
Ted
Ted 2015-7-14
Thanks for the help. Try:
clean = [40 10 50 30 40 10 50 30 40 10 50 30];
lost = [40 0 50 30 0 10 0 0 40 10 50 30];
It should give:
desired = [40 60 30 50 120 10 50 30];
Your solution does not.

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Sean de Wolski
Sean de Wolski 2015-7-14
accumarray(interp1(find(lost),1:nnz(lost),1:numel(lost),'next')',clean)
  4 个评论
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