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hours(diff​(datetime(​[t1;t2]))) function

조회 수: 1(최근 30일)
Berk Opla
Berk Opla 2021년 7월 12일
답변: Peter Perkins 2021년 7월 27일
i have a 300 x 2 table, i want to calculate time differences and i want to count how many of them are more than 3 hours. [a, b] is the size of the table. it gives an error in the = c line & it says Unable to use a value of type duration as an index. how do i solve this?
below is the related part of the code. thank you so much
for n = 1:a
t1 = y(n,1)
t2 = y(n,2)
hours(diff(datetime(t1;t2]))) = c
if c > 3
x = x+ 1
end
end
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Berk Opla
Berk Opla 2021년 7월 12일
yes i'm getting "Unable to use a value of type duration as an index." for the line of
hours(diff(datetime(t1;t2]))) = c

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채택된 답변

Berk Opla
Berk Opla 2021년 7월 12일
편집: Berk Opla 2021년 7월 12일
figured it out
hours(diff(datetime(t1;t2]))) = c is wrong
it should be c = hours(diff(datetime([t1;t2])))
for some reason
  댓글 수: 2
Berk Opla
Berk Opla 2021년 7월 12일
yeah fixed it now. the problem was the place of the c

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추가 답변(2개)

dpb
dpb 2021년 7월 12일
hours(diff(datetime(t1;t2]))) = c
You're using hours that is a builtin function as an array name on the LHS of an assignment statement and you also have an unmatched "]" bracket in the expression.
You also don't need a loop here...use MATLAB vectorized operations instead...
You don't provide what y variable contains; presuming it can be converted to a datetime, then if the answer is to determine how many of the time differences between the two columns are > 3 hours, then
nGt3=sum((datetime(y:,1)-datetime(y:,2))>3);
This presumes as your code that the first date is in the second column not the first -- one would normally think that would be the other way 'round; in which case would want to reverse the column indices in the difference calculation.

Peter Perkins
Peter Perkins 2021년 7월 27일
In addition to what others have said, you probably don't need the "hours" in
hours(diff(datetime(t1;t2])))
All that does is turn the duration that diff returns into a number. You are probably better off leaving it as duration, and replacing "3" with hours(3). More expressive.

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