Extract rows in one array based on time values in a another array +20 seconds

I have two arrays. Array A is a 29 x 1 vector that includes different times that an event occurred. Array B is a 1410 x 4 matrix where the first column contains time values as well (some times are the same as those in matrix A and some are different).

Truncated example of array A:

399.760000000000

400.140000000000

400.390000000000

400.760000000000

Truncated example of array B:

399.010000000000 2 1 NaN

399.760000000000 16 NaN NaN

400.140000000000 16 NaN NaN

400.390000000000 16 NaN NaN

400.760000000000 16 NaN NaN

401.630000000000 NaN NaN 45.4277500000000

405.080000000000 NaN NaN 45.3810000000000

413.320000000000 NaN NaN 42.3262500000000

415.950000000000 NaN NaN 43.1500000000000

420.200000000000 NaN NaN 38.6815000000000

422.750000000000 NaN NaN 38.0767500000000

429.250000000000 NaN NaN 44.4442500000000

What I want to do is extract all the rows in array B that are equal to the times in array A but also any rows in array B that are within a +20 second time window of the times in array A. So, from the above example I would want this:

Array C =

399.760000000000 16 NaN NaN

400.140000000000 16 NaN NaN

400.390000000000 16 NaN NaN

400.760000000000 16 NaN NaN

401.630000000000 NaN NaN 45.4277500000000

405.080000000000 NaN NaN 45.3810000000000

413.320000000000 NaN NaN 42.3262500000000

415.950000000000 NaN NaN 43.1500000000000

420.200000000000 NaN NaN 38.6815000000000

I have tried converting both A and B to times tables and using tolerances but I can't seem to get it to work correctly. I'm thinking using some kind of tolerance code may be the way to go but I have tried it many different ways and can't get it to work the way I want. Plus, tolerances want to look both +/-20 seconds when I really only need to look +20 seconds forward in time. Any help is much appreciated. I'm happy to make any clarifications if need be. Thanks.

Answer 1

[Akira Agata]

Simple and straight-forward way would be like this.

Just in case, I have saved your truncated example of array A and B as .mat file and attached here.

idx = false(size(B,1),1);
for kk = 1:numel(A)
  idx = idx | (B(:,1) >= A(kk) & B(:,1) <= A(kk) + 20);
end

C = B(idx,:);

[SRB]

Works great. Thanks!

Answer 2

[Peter Perkins]

I'm not 100% following, but I would think a timetable would be your friend here. The following selects rows of a timetable that are at or no more than 20s after two specified times:

>> tt = timetable((1:10)','RowTimes',seconds(sort(100*rand(10,1))))
tt =
  10×1 timetable
       Time       Var1
    __________    ____
    18.687 sec      1 
    27.603 sec      2 
    38.156 sec      3 
    44.559 sec      4 
    48.976 sec      5 
    64.631 sec      6 
    70.936 sec      7 
    75.469 sec      8 
    76.552 sec      9 
    79.52 sec      10 
>> timesOfInterest = seconds(sort(100*rand(2,1)))
timesOfInterest = 
  2×1 duration array
   34.039 sec
   58.527 sec
>> tt(withtol(timesOfInterest+seconds(10),seconds(10)),:)
ans =
  7×1 timetable
       Time       Var1
    __________    ____
    38.156 sec     3  
    44.559 sec     4  
    48.976 sec     5  
    64.631 sec     6  
    70.936 sec     7  
    75.469 sec     8  
    76.552 sec     9