Merging two tables based on time interval

I have two tables A and B. A consists of information about glucose measurements, B consists insulin medication settings. I want to couple a glucose measurement to the setting of the insulin perfusor. However the timing is different and there are more medication settings than glucose measurements.

Table A:

Patientnumber * MeasureGlucose * Time(using datenum) * TimeNormal

11112222 * 16,9 * 7.3626e+05 * 26-10-2015 17:57:00

11112222 * 21,5 * 7.3626e+05 * 26-10-2015 19:47:00

11112222 * 26,3 * 7.3626e+05 * 26-10-2015 22:09:00

11112222 * 15,6 * 7.3626e+05 * 26-10-2015 02:29:00

11112222 * 8,8 * 7.3626e+05 * 26-10-2015 06:10:00

Table B:

Patientnumber * PerfusorNovorapidDosisE_u * Time(using datenum) * TimeNormal

11112222 * 1 * 7.3626e+05 * 26-10-2015 17:44:00

11112222 * 2 * 7.3626e+05 * 26-10-2015 20:00:00

11112222 * 4 * 7.3626e+05 * 26-10-2015 22:12:00

11112222 * 4 * 7.3626e+05 * 27-10-2015 02:07:00

11112222 * 4 * 7.3626e+05 * 27-10-2015 04:05:00

11112222 * 4 * 7.3626e+05 * 27-10-2015 06:05:00

11112222 * 2 * 7.3626e+05 * 27-10-2015 08:10:00

How can I merge these tables in the following way:

1. Select time of measurement in table A.

2. Find a medication setting within 40 minutes after the measurement

3. If no medication setting available in step 2, use the previous medication setting

I hope someone can help me with this problem setting.

Answer 1

[Udit Gupta]

You can use

 t = interp1(sample_time,tableB.Time,'nearest');
 if abs(sample_time-t <= 40/(24*60))
     <Update medication setting using t>
 else
     <Use previous setting>
 end

See interp1 documentation for more control.