Having trouble getting this find work properly

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liu James 2016-12-20

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评论： KSSV 2016-12-21

I have two cell arrays where the first one is time converted into serial date and the second cell array (bb) which has specific times associated with other data in it. I'm trying to extract the rows in bb in chronological order by using time cell array. BB cell array is a 1x34 cell array where each cell once expanded is a nx7 array.

I am rather new at this, but I came up with this, and I can't get this working correctly as well as do what I want it to do. Not even sure if it is in the right direction.

I'm trying to find the serial date in the test1 file in all columns of bb (1x34) and extract it into another matrix when I call the first row of time (test1). BB's {1x34}(nx7) the column 7 of the nx7 is the serial date for that BB.

for i=1:length(test1)
    for t=1:length(bb)
        for w=1:length(bb{t})
            [a{t} b(w,1:7)]=find(bb{t}(w,1:7)==test1(i)
        end
    end
end

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回答（1 个）

KSSV 2016-12-20

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don't use find, check with ismemebr, ismemebrtol.

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liu James 2016-12-21

在 MATLAB Online 中打开

If I'm understood what you said, the find will not extract it because of the extra decimals even though they are 0 is that correct? However, if I type this

[a b]=find(test1(589)==bb{1}(1,7))
a =
            1.00
b =
            1.00

it will show that there is a position vs empty matrix.

[a b]=find(test1(590)==bb{1}(1,7))
a =
       []
b =
       []

KSSV 2016-12-21

在 MATLAB Online 中打开

You fix a small parameter eps and subtract them.

eps = 10^-6 ;
idx = test1(589)-bb{1}(1,:)<eps

so in idx if any value is 1, then you can say they are equal. Using == for flottant numbers is not advisable. Also, I suggested you to use ismembertol.

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