Extract rows from a matrix using time ranges

4 views (last 30 days)
Hello everyone, i have a problem. I have to extract rows from a matrix using time ranges (each row between those dates), for example
mi matrix look like,
A=734139 2 1.2
734140 3 1.4
734141 10 0.4
734142 8 0.1
734143 14 2.1
734144 20 4.3
734145 1 5.1
734146 2 3.1
734147 3 2.1
734148 2 1.3
And i have other matrix with time ranges for example (initial date and final date of ranges):
B= 734139 734141
734145 734145
I expect have this
C= 734139 2 1.2
734140 3 1.4
734141 10 0.4
734145 1 5.1
734146 2 3.1
I know how did it with the new time tools (like timetables for example).. in fact is done, but i must use only basic tools because i'm translatting this code for old products (matlab2012a specifically) and octave.
Thank you for your help!

Accepted Answer

Rik
Rik on 8 May 2019
I'm going to assume your last element of B should be 1 larger, because then your C makes sense. The code below should do what you need by looping over your different time segments.
A= [734139 2 1.2
734140 3 1.4
734141 10 0.4
734142 8 0.1
734143 14 2.1
734144 20 4.3
734145 1 5.1
734146 2 3.1
734147 3 2.1
734148 2 1.3];
B= [734139 734141
734145 734146];
row=false(size(A,1),1);
t_=A(:,1);
for k=1:size(B,1)
t1=B(k,1);t2=B(k,2);
row=row | (t_>=t1 & t_<=t2);
end
C=A(row,:);
clc
fprintf('%6d %02d %3.1f\n',C')
  4 Comments

Sign in to comment.

More Answers (1)

Peter Perkins
Peter Perkins on 8 May 2019
dulio, I strongly recommend that you use datetims and timetables. You will likely be happier in the long run:
>> X = [734139 2 1.2
734140 3 1.4
734141 10 0.4
734142 8 0.1
734143 14 2.1
734144 20 4.3
734145 1 5.1
734146 2 3.1
734147 3 2.1
734148 2 1.3];
>> t = array2table(X,'VariableNames',{'Date' 'X' 'Y'});
>> t.Date = datetime(t.Date,'ConvertFrom','datenum','Format','dd-MMM-yyyy');
>> tt = table2timetable(t)
tt =
10×2 timetable
Date X Y
___________ __ ___
01-Jan-2010 2 1.2
02-Jan-2010 3 1.4
03-Jan-2010 10 0.4
04-Jan-2010 8 0.1
05-Jan-2010 14 2.1
06-Jan-2010 20 4.3
07-Jan-2010 1 5.1
08-Jan-2010 2 3.1
09-Jan-2010 3 2.1
10-Jan-2010 2 1.3
>> dt = datetime([734139 734141],'ConvertFrom','datenum')
dt =
1×2 datetime array
01-Jan-2010 00:00:00 03-Jan-2010 00:00:00
>> tr = timerange(dt(1),dt(2))
tr =
timetable timerange subscript:
Select timetable rows with times in the half-open interval:
[01-Jan-2010 00:00:00, 03-Jan-2010 00:00:00)
See Select Timetable Data by Row Time and Variable Type.
>> tt1 = tt(tr,:)
tt1 =
2×2 timetable
Date X Y
___________ _ ___
01-Jan-2010 2 1.2
02-Jan-2010 3 1.4
  3 Comments
duilio fonseca
duilio fonseca on 8 May 2019
Hi Peter, thank you very much in fact i'm using those functions in my original code. But how Adams writes, i have to run this in r2012a product.

Sign in to comment.

Categories

Find more on Dates and Time in Help Center and File Exchange

Products

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!