How can I determine the indices and length of consecutive non-NaN values in an array?

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Jonathan Macuroy
Jonathan Macuroy 2019-6-28
评论： Stephen23 2019-6-29
Say I have a vector A = [NaN NaN NaN 10 22 NaN 33 28 21 NaN 20 98 NaN], how do I:
1) determine the indices of consecutive non-NaN values; and
2) extract the count and length of these 'consecutive events'
Thank you!

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采纳的回答

Stephan
Stephan 2019-6-28
编辑：Stephan 2019-6-28
1. FInd the indexes:
B = find(isnan(A))
2. To find consecutive blocks you could use the diff function on a logical array:
C = isnan(A) % gives a logical array
diff(C) % --> is different from zero, when a block changes (1 for start and -1 for end of block)

更多回答（1 个）

Stephen23
Stephen23 2019-6-28
编辑：Stephen23 2019-6-28
1)
>> A = [NaN NaN NaN 10 22 NaN 33 28 21 NaN 20 98 NaN];
>> find(~isnan(A))
ans =
4 5 7 8 9 11 12
or do you mean something else by "consecutive non-NaN values" ? Do you only want to get the indices at the beginning+end of each run of non-NaNs ?
2)
>> D = diff([false,~isnan(A),false]);
>> L = find(D<0)-find(D>0) % length
L =
2 3 2
>> N = numel(L) % count
N = 3

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