Convert date data in datetime

19 vues (au cours des 30 derniers jours)
PS
PS le 19 Déc 2023
Dear Matlab Community,
I have uplaoded the small subset of the data which I am using;
I am converting it in dateime using:
date = datetime(string(data.Date),'InputFormat','yyyyMMddHH' ) ;
I have also attached the output file.
I will also like to add that the original file is in csv format, I am using 'readtable' to read and process it in Matlab.
The problem is date corresponding to 24hrs is not coverted in datetime.
Any help will be highly appreciated.
Many thanks.
  5 commentaires
Stephen23
Stephen23 le 19 Déc 2023
"I will also like to add that the original file is in csv format, I am using 'readtable' to read and process it in Matlab."
Please upload a sample CSV file, to see if the importing can be improved.
PS
PS le 20 Déc 2023
Modifié(e) : PS le 20 Déc 2023
@Stephen23, I will not be upload the file due to some reasons. But importing has been done correctly and the sample I have uploaded are the exact values given in the csv file.
Thanks

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Réponse acceptée

Dyuman Joshi
Dyuman Joshi le 19 Déc 2023
Déplacé(e) : Dyuman Joshi le 19 Déc 2023
"The problem is date corresponding to 24hrs is not coverted in datetime."
Yes, because in 24 hour format, the hours are counted from 0 to 23.
A work around which works for the data in the given format -
load('data.mat')
format longg
date = datetime(string(data.Date - 1),'InputFormat','yyyyMMddHH')
date = 49×1 datetime array
01-Jan-2016 00:00:00 01-Jan-2016 01:00:00 01-Jan-2016 02:00:00 01-Jan-2016 03:00:00 01-Jan-2016 04:00:00 01-Jan-2016 05:00:00 01-Jan-2016 06:00:00 01-Jan-2016 07:00:00 01-Jan-2016 08:00:00 01-Jan-2016 09:00:00 01-Jan-2016 10:00:00 01-Jan-2016 11:00:00 01-Jan-2016 12:00:00 01-Jan-2016 13:00:00 01-Jan-2016 14:00:00 01-Jan-2016 15:00:00 01-Jan-2016 16:00:00 01-Jan-2016 17:00:00 01-Jan-2016 18:00:00 01-Jan-2016 19:00:00 01-Jan-2016 20:00:00 01-Jan-2016 21:00:00 01-Jan-2016 22:00:00 01-Jan-2016 23:00:00 02-Jan-2016 00:00:00 02-Jan-2016 01:00:00 02-Jan-2016 02:00:00 02-Jan-2016 03:00:00 02-Jan-2016 04:00:00 02-Jan-2016 05:00:00
  4 commentaires
Fangjun Jiang
Fangjun Jiang le 19 Déc 2023
If the data.Date in data.mat is the best format that you prefer, you could apply the same "duration" idea.
date = datetime(string(data.Date - 1),'InputFormat','yyyyMMddHH')+hours(1)
PS
PS le 20 Déc 2023
@Dyuman Joshi..this dataset is just a tiny sample from the large number of files I have. I have been given data in the format of 1-24hrs range, so I want to sick to that. But thanks for your solution
@Fangjun Jiang.. thanks for the solution, I think I can work with that.

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Plus de réponses (2)

Fangjun Jiang
Fangjun Jiang le 19 Déc 2023
Modifié(e) : Fangjun Jiang le 19 Déc 2023
You could treat the last two digits as duration. Code below is not optimized but gives the correct result.
load Data.mat;
date_data=char(string(data.Date));
a=char(date_data);
b=a(:,1:end-2);
c=a(:,end-1:end);
d=datetime(b,'InputFormat','yyyyMMdd')+hours(str2num(c))
02-Jan-2016 20:00:00
02-Jan-2016 21:00:00
02-Jan-2016 22:00:00
02-Jan-2016 23:00:00
03-Jan-2016 00:00:00
03-Jan-2016 01:00:00
  1 commentaire
PS
PS le 20 Déc 2023
Modifié(e) : PS le 20 Déc 2023
@Fangjun Jiang Thanks for this solution too, I have also found a workaround using insertAfter and replace. I will probably use first solution provided by you.

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Seth Furman
Seth Furman le 2 Jan 2024
Another solution is the numeric datetime constructor syntax (i.e. t = datetime(Y,M,D,H,MI,S)), which allows values outside the conventional range:
"If an element of the Y, M, D, H, MI, or S inputs falls outside the conventional range, then datetime adjusts both that element and the same element of the previous input."
Since your timestamps always have the same field widths, you can 1) extract each field, 2) convert to numeric, and 3) call the datetime constructor.
load data.mat
% Convert Date to string
data = convertvars(data, "Date", "string");
% Extract date and time fields
data = addvars(data, extractBetween(data.Date, 1, 4), Before=1, NewVariableNames="Year");
data = addvars(data, extractBetween(data.Date, 5, 6), After=1, NewVariableNames="Month");
data = addvars(data, extractBetween(data.Date, 7, 8), After=2, NewVariableNames="Day");
data = addvars(data, extractBetween(data.Date, 9, 10), After=3, NewVariableNames="Hour");
% Convert fields to numeric
data = convertvars(data, ["Year","Month","Day","Hour"], "double");
% Construct datetime
data = addvars(data, datetime(data.Year, data.Month, data.Day, data.Hour, 0, 0), Before=1, NewVariableNames="Datetime");
tail(data)
Datetime Year Month Day Hour Date Value ____________________ ____ _____ ___ ____ ____________ _____ 02-Jan-2016 18:00:00 2016 1 2 18 "2016010218" 31 02-Jan-2016 19:00:00 2016 1 2 19 "2016010219" 24 02-Jan-2016 20:00:00 2016 1 2 20 "2016010220" 29 02-Jan-2016 21:00:00 2016 1 2 21 "2016010221" 29 02-Jan-2016 22:00:00 2016 1 2 22 "2016010222" 25 02-Jan-2016 23:00:00 2016 1 2 23 "2016010223" 30 03-Jan-2016 00:00:00 2016 1 2 24 "2016010224" 26 03-Jan-2016 01:00:00 2016 1 3 1 "2016010301" 37

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