An easy Array question

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Hello kity
Hello kity 2012-12-12
I have a set of data seprated by Nans, example; DATA= [1; 2; 3; 4; NaN ; 6 ;7 ; NaN]
I want to do a calculation in every set of rows (example 1- 4 and 6-7).
So I programmed and found all the begin and end indices of each row (in this example, begin [ 1 ; 4] and end [6 ; 7]).
so this is what i want: Have two columns with begin and end indices;
column 1; A=[1 ; 6 ] %%%these are the begin indices
column 2; B[ 4 ;7 ] %%these are the end indices
now i want created a new array (call it new array) that has counted 1-4 and 6-7.
Then all i need to do is out=data(newarray) and i ll have my rows which i use for calc

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回答（2 个）

Sean de Wolski
Sean de Wolski 2012-12-12
Are you sure you need a cell array?
I would just use a for-loop and loop over the start and end indices:
sidx = start index
eidx = end index
for ii = 1:numel(eidx)
do_something_with(X(sidx(ii):eidx(ii)));
end
Of course this is also how I would build the cell array (i.e. replace
do_something_with with C(idx) = {}
And preallocate C with
C = cell(numel(sidx,1));
  1 个评论
Hello kity
Hello kity 2012-12-12
i changed my question a bit, maybe it is more clear now.

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Andrei Bobrov
Andrei Bobrov 2012-12-13
编辑：Andrei Bobrov 2012-12-13
DATA= [1; 2; 3; 4; NaN ; 6 ;7 ; NaN];
a = [1;4];
b = [6;7];
d = DATA(~isnan(DATA));
out = mat2cell(d(:),[diff(a)+1,diff(b)+1],1);
  2 个评论
Jan
Jan 2012-12-13
I think there must be a ~ before isnan.
Andrei Bobrov
Andrei Bobrov 2012-12-13
编辑：Andrei Bobrov 2012-12-13
Hi Jan, thank you. Corrected.

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