Problems with indexing into an array with nan (indexing on 2 variables)

Question

PAK 2018-8-23

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/415892-problems-with-indexing-into-an-array-with-nan-indexing-on-2-variables

评论： PAK 2018-8-30

Hi All,

I'm having trouble using a logical variable ( Bandphase_logical = 9x5272240 logical) to find "true" events in another variable ( bandphase = 3x5272240 single). I think part of my problem is that the "bandphase" variable contains NaNs and I am trying to index over 2 different variables (see below).

"Bandphase_logical" contains 1's where an event occurs across a time series (5272240 samples). "bandphase" contains radian values across the entire timeseries (5272240 samples). Each row contains different frequency bands, and has a "NaN" where that sample does that have a frequency.

I'd like to do something along the lines of (I'd to create a loop where the bandphase variable changes adaptively with how many rows it has and same with the Bandphase_logical variable [e.g.: if bandphase had 5 rows and Bandphase_logical had 12 rows]):

bandphase(1,:)(Bandphase_logical(1,:)
bandphase(1,:)(Bandphase_logical(2,:)
.
.
bandphase(1,:)(Bandphase_logical(9,:)
bandphase(2,:)(Bandphase_logical(1,:)
bandphase(2,:)(Bandphase_logical(2,:)
.
.
bandphase(2,:)(Bandphase_logical(9,:)
bandphase(3,:)(Bandphase_logical(1,:)
bandphase(3,:)(Bandphase_logical(2,:)
.
.
bandphase(3,:)(Bandphase_logical(9,:)

I'd greatly appreciate any help! I'm thoroughly confused.

PK

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Answer 1

Stephen23 2018-8-23

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/415892-problems-with-indexing-into-an-array-with-nan-indexing-on-2-variables#answer_333795

编辑：Stephen23 2018-8-23

在 MATLAB Online 中打开

for ii = 1:size(bandphase,1)
    for jj = 1:size(Bandphase_logical,1)
        tmp = bandphase(ii,:);
        tmp(Bandphase_logical(jj,:))
    end
end

To store the output (of different sizes) use a cell array:

S = [size(bandphase,1),size(Bandphase_logical,1)];
C = cell(S);
for ii = 1:S(1)
    for jj = 1:S(2)
        tmp = bandphase(ii,:);
        C{ii,jj} = tmp(Bandphase_logical(jj,:))
    end
end