add 'dd-MMM-yyyy' data to datetime array in form 'HH:mm:ss:SSS' with rollover
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I need to add calendar date information to an array of datetime data in the form 'HH:mm:ss:SSS', i have the date that the data starts being collected on and a snippet of the data looks like this
'23:59:59:873'
'23:59:59:893'
'23:59:59:933'
'23:59:59:963'
'00:00:00:003'
'00:00:00:043'
'00:00:00:073'
'00:00:00:103'
I know how to reformat the datetime data so it includes the calendar information and assign a year month and day to the data with
TimeData.Format = 'dd-MMM-yyyy HH:mm:ss:SSS';
TimeData.Year = startTime.Year;
TimeData.Month = startTime.Month;
TimeData.Day = startTime.Day;
This makes the data look like
'04-Jan-2023 23:59:59:873'
'04-Jan-2023 23:59:59:893'
'04-Jan-2023 23:59:59:933'
'04-Jan-2023 23:59:59:963'
'04-Jan-2023 00:00:00:003'
'04-Jan-2023 00:00:00:043'
'04-Jan-2023 00:00:00:073'
'04-Jan-2023 00:00:00:103'
Im wondering how to go about providing the TimeData array a start date, and have it update the date as the data rolls over 24 hours to a new day, having the data look like this
'04-Jan-2023 23:59:59:873'
'04-Jan-2023 23:59:59:893'
'04-Jan-2023 23:59:59:933'
'04-Jan-2023 23:59:59:963'
'05-Jan-2023 00:00:00:003'
'05-Jan-2023 00:00:00:043'
'05-Jan-2023 00:00:00:073'
'05-Jan-2023 00:00:00:103'
0 个评论
采纳的回答
Star Strider
2023-1-11
编辑:Star Strider
2023-1-12
I’m not certain how robust this is, however it seems to work in this example —
Times = ['23:59:59:873'
'23:59:59:893'
'23:59:59:933'
'23:59:59:963'
'00:00:00:003'
'00:00:00:043'
'00:00:00:073'
'00:00:00:103'];
Time = datetime([Times; Times; Times], 'InputFormat','HH:mm:ss:SSS'); % Repeat To Test Code
DI = cumsum([0; diff(hour(Time))<0]); % Day Increment
Date = datetime('04-Jan-2023') + days(DI); % 'Date' Vector
DateTime = Date + timeofday(Time); % Date + Time
DateTime.Format = 'dd-MMM-yyyy HH:mm:ss.SSS'
It works by creating the ‘DI’ (‘Day Increment’) vector, and adding it appropriately to the successive days. Try it on your complete data set to see if it gives the desired result.
EDIT — (12 Jan 2023 at 00:36)
Changed ‘~=0’ to ‘<0’ in the ‘DI’ calculation.
.
4 个评论
dpb
2023-1-11
Times = ['23:59:59:873'
'23:59:59:893'
'23:59:59:933'
'23:59:59:963'
'00:00:00:003'
'00:00:00:043'
'00:00:00:073'
'00:00:00:103'];
Time = datetime(Times,'InputFormat','HH:mm:ss:SSS');
Time=[Time;Time(5:end)+hours(1);]; % add an hour turnover besides day
Time=repmat(Time,2,1); % and another copy to test
DI = cumsum([0; diff(hour(Time))~=0]); % Day Increment
Date = datetime('04-Jan-2023') + days(DI); % 'Date' Vector
DateTime = Date + timeofday(Time); % Date + Time
DateTime.Format = 'dd-MMM-yyyy HH:mm:ss.SSS'
What afraid of, @Star Strider, the test for ~0 turns over a day for every hour change, not just rollover at midnight...
Star Strider
2023-1-11
编辑:Star Strider
2023-1-12
@Leo Rogers — My pleasure!
The ‘DI’ vector is set to increment only when there is an abrupt negative change in the hours difference. It shouldn’t increment in any othe condition, providing the hours are always in a 24-hour cycle. A 12-hour cycle with AM and PM would break it, and I would need to figure out a way to deal with that.
Note added in proof —
v = linspace(0, 23, 4).'*ones(1,5);
v = v(:).';
DI = cumsum([0 diff(v)<0]);
A = [fix(v); DI]
EDIT — (12 Jan 2023 00:40)
Added example.
.
更多回答(2 个)
dpb
2023-1-11
编辑:dpb
2023-1-11
Times = ['23:59:59:873'
'23:59:59:893'
'23:59:59:933'
'23:59:59:963'
'00:00:00:003'
'00:00:00:043'
'00:00:00:073'
'00:00:00:103'];
Time = datetime(Times,'InputFormat','HH:mm:ss:SSS');
Time=[Time;Time(5:end)+hours(1);]; % add an hour turnover besides day
Time=repmat(Time,2,1); % and another copy to test
DI = cumsum([0; diff(hour(Time))<0]); % Day Increment
Date = datetime('04-Jan-2023') + days(DI); % 'Date' Vector
DateTime = Date + timeofday(Time); % Date + Time
DateTime.Format = 'dd-MMM-yyyy HH:mm:ss.SSS'
OK, at least a first blush it appears that simply checking to be sure the hour rollover is <0 will work; again the caveat about dealing with DST.
I've always wondered why TMW didn't introduce some tools with the timetable or just with datetime class to help with the rollover issues -- I've found several times that the rollover bug bit and no real help available to deal with it at higher level. I can't think of the specific examples at the moment, unfortunately, but I do recall having had difficulties...
0 个评论
Leo Rogers
2023-1-12
11 个评论
youma
2023-4-12
You're a life saver, you know that?
So yes, you rcomment made me wonder, cause I had a timetable in the beginning but while working with meteo_data I had to put it into this format'yyyy-mm-dd HH:MM:SS' at some point so I used "datestr", and forgot that I even used it.
Thanks again, it worked!!
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