Creating a vector to list values occurring within 5 seconds before a designated time

I have the following data:

buzz time  click time
16948    16942.58755
16966.2    16942.77004
17048.7    16942.95203
17090.5    16943.14491
17104.4    16943.32836
17111.8    16943.51334
17138.1    16943.69869
17178.3    16943.88338
    16944.06336
    16944.23747
    16944.42053
    16944.60682
    16944.78904
    16944.97181
    16945.15974
    16945.35162
    16945.53905
    16945.72622
    16945.91283
    16946.1051
    16946.28659
    16946.46027
    16946.62662
    16946.80914
    16946.99274
    16947.18359
    16947.37839
    16947.56643
    16947.75977
    16951.8645
    16952.04876
    16952.24642
    16952.42928
    16952.62402
    16952.81478
    16953.00297
    16953.19304
    16953.38403
    16953.58685
    16953.7825
    16953.97595
    16954.17543
    16954.38145
    16954.57069
    16954.75829
    16954.95385
    16955.15018
    16955.36247
    16955.5849
    16955.81282
    16956.03784
    16956.24667
    16956.45085
    16956.66187
    16956.88283
    16957.09311
    16957.30488
    16957.51525
    16957.71652
    16957.9289
    16958.12451
    16958.33015
    16958.53322
    16958.74688
    16958.92939
    16959.12829
    16959.38434
    16959.57244
    16959.77432
    16962.28846
    16962.49168
    16962.69591
    16962.89133
    16963.10165
    16963.28117
    16963.44878
    16963.62042
    16963.7931
    16963.9592
    16964.18957
    16964.37206
    16964.56041
    16964.75655
    16964.94539
    16965.12754
    16965.31854
    16965.49747
    16965.68268
    16965.8561
    16966.03613

Given this data, I am trying to find a code that will allow me to create a vector with each row containing all of the click times occurring within 5 seconds before the buzz time for each buzz. For example, if the data above were to be used, I would see an array with 8 rows (since there are 8 buzzes in this example), with each of the rows containing the values for the click times within 5 seconds before the corresponding buzz time. Is this possible to do in MatLab? Thanks for your help!

[Azzi Abdelmalek]

Your question is not clear, what is the expected result?

[Mariana Kneppers]

essentially, I need a way to get a listing of all of the click times occurring within the 5 seconds leading up to every buzz time. I don't think it is possible unless you make the cell array like Kelly proposed below. However, the code given isn't necessarily giving me the proper listings needed. Do you have any proposed solution to this? Thanks!

Answer 1

[Kelly Kearney]

In your example, the number of clicks corresponding to a particular buzz is not the same for all buzzes, so storing as rows of a matrix isn't possible (unless you pad out some of the rows with placeholders). A cell array would be a better choice. Assuming buzz and click are both column vectors:

isclose = num2cell(abs(bsxfun(@minus, buzz', click)) < 5, 1);
closeclicks = cellfun(@(mask) click(mask), isclose, 'uni', 0);

[Mariana Kneppers]

I didn't even realize you could do that, that's super useful! The code almost works, but for some reason the first cell in the resulting cell array lists the clicks 5 seconds before AND AFTER the buzz time (I only want the 5 seconds before). However, the second cell array is correct and only gives me the listings for 5 seconds before. Do you know why this could be happening? Thanks again for your help!

[Kelly Kearney]

Sorry, misread your question as within 5 seconds rather than only 5 secs before. Not sure why you're seeing correct answers for the closeclicks array as defined above, though

buzz = [20 30]';
click = rand(50,1)*100;

dt = bsxfun(@minus, buzz', click);

% Within 5 secs

isclose = num2cell(abs(dt) <= 5, 1);
closeclicks1 = cellfun(@(mask) click(mask), isclose, 'uni', 0);

% 5 secs before only

isclose = num2cell(dt >= 0 & dt <= 5, 1);
closeclicks2 = cellfun(@(mask) click(mask), isclose, 'uni', 0);