Please advice how to convert date array to seconds format
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NN
2021-1-18
here by attaching date formats and their respective code, kindly advice how can i convert it to seconds form as attached..
Data=readtable('axeaload.xlsx');
testdates = Data{1:end,1};
date_num = datenum(testdates);
14 个评论
Walter Roberson
2021-1-18
Seconds since what time?
Or based upon what input?
datenum reflect full days. Seconds on the order of 120 reflect approximately every 2 minutes.
It seems more likely that you have a duration of some kind inside your xlsx file.
NN
2021-1-18
thanks for your reply .I have attached the excel file .Please check
But i understand it is hourly basis in excel file
Walter Roberson
2021-1-18
Might I suggest that what you want is minutes and not seconds?
Data = readtable('axeaload.xlsx');
dt = Data{:,1} + hours(Data{:,2});
minutes_inside_day = minutes(dt - dateshift(dt, 'start', 'day'));
minutes_since_start = minutes(dt - dateshift(dt(1), 'start', 'day'));
Depending what you are trying to do.
If you are wanting to do minutes inside the day, then a simpler way is just
minutes_inside_day = Data{:,2} * 60;
NN
2021-1-18
Thank you it works, but why it shows from 120,then 180...
Its not showing 60 sec initially !
Walter Roberson
2021-1-18
... It doesn't start with 120 ?
Data = readtable('axeaload.xlsx');
dt = Data{:,1} + hours(Data{:,2});
minutes_inside_day = minutes(dt - dateshift(dt, 'start', 'day'));
minutes_since_start = minutes(dt - dateshift(dt(1), 'start', 'day'));
minutes_inside_day(1:3)
ans = 3×1
60
120
180
minutes_since_start(1:3)
ans = 3×1
60
120
180
minutes_inside_day = Data{:,2} * 60;
minutes_inside_day(1:3)
ans = 3×1
60
120
180
Perhaps the 60 scrolled off your command window and you need to scroll back to see it?
Walter Roberson
2021-1-18
Try
Data = readtable('axeaload.xlsx', 'readvariablenames', false);
I speculate you might be using an older version that tended to be weaker in figuring out whether the first line was variable names or not.
NN
2021-1-19
I request you to look into the below query as well.
When i import time series data from matlab to simulink,it appears as individual data not as corresponding to time.(image attached).
i used the below format for below workspace
[time Youtput]
time and Youtput are 1*360 double format
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/492584/image.png)
NN
2021-1-19
this has been posted here :
https://www.mathworks.com/matlabcentral/answers/720499-importing-data-rom-matlab-to-simulink
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