Create new variable with only values of a certain variable

Question

Mary Hemler 2020-6-1

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/539878-create-new-variable-with-only-values-of-a-certain-variable

编辑： Tommy 2020-6-1

I want to save a new variable 'highMI_sec' as only the values of mutualInfoTotal that are at least equal to 5 (at end of code). How can I do this?

for i = 1:n_cells
    spikes = cellspikes{i}; % access cellspikes
    spikes = spikes./1000; % ms to secs
    spikes = spikes(spikes>startTime&spikes<stopTime);
    edgesT = linspace(startTime,stopTime,numel(trackingtimes)+1);
    binnedSpikes = histcounts(spikes,edgesT);% sorts spikes into bins
    % also bin headangle data
    n_bins_angle = 60;
    edgesHD = linspace(min(headangle), max(headangle), n_bins_angle +1);
    [occupancy,~,angle_inds] = histcounts(headangle,edgesHD); 
    for iBin = 1:n_bins_angle
        spikesPerAngle(iBin) = sum(binnedSpikes(angle_inds == iBin));
    end
    SPA(1,i)={spikesPerAngle};
    % compute average firing rate for each HD angle
    firing_rate = spikesPerAngle./(occupancy.*deltaT); %this vector is a TUNING CURVE!
    FR(1,i) = {firing_rate};
    
    % now compute individual pieces needed to compute mutual info
    probability_density = occupancy./sum(occupancy); %proportion of time spent at each HD angle per total occupancy at all angles
    PD(1,i)={probability_density};
    % compute average firing rate across all HD angles
    mean_rate = numel(spikes)./(stopTime-startTime);
    MR(1,i) = mean_rate;
    % compute mutual info between firing rate and HD
    mutualInfo = sum(firing_rate .* log2(firing_rate./mean_rate) .* probability_density,'omitnan'); 
    MIperspike = mutualInfo./(mean_rate);
    %store mutual info for each cell into a matrix
    mutualInfoTotal(1,i) = mutualInfo; %in bits per second
    MISpikeTotal(1,i) = MIperspike;
end

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Answer 1

Tommy 2020-6-1

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/539878-create-new-variable-with-only-values-of-a-certain-variable#answer_444350

在 MATLAB Online 中打开

Try this:

idx = mutualInfoTotal >= 5; % indices of values at least equal to 5
mutualInfoTotal = mutualInfoTotal(idx);

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Mary Hemler 2020-6-1

Okay, that worked, thanks. but the first statement didn't actually give me the indices of the values at least equal to 5 (it gave me a logical array). How can I find out the indices of the values at least equal to 5? I am trying to use that for my next step.

Tommy 2020-6-1