Convert date data in datetime
显示 更早的评论
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 个评论
the cyclist
2023-12-19
Rather than pasting the data (which is potentially ambiguous as to how it is stored), can you upload the data in a MAT file? You can use the paper clip icon in the INSERT section of the toolbar.
Here is a simpler, self-contained example that illustrates @PS's question. The last element does not convert (because the hour is listed as '24'):
date_data = ["2016010101","2016010113","2016010124"];
datetime(date_data,'InputFormat','yyyyMMddHH')
PS
2023-12-19
Stephen23
2023-12-19
"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.
采纳的回答
"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')
4 个评论
PS
2023-12-19
Dyuman Joshi
2023-12-19
But there are only 49 elements in the array above.
Also, (I guess) you want to display the hours in 1-24 range, which is not possible in MATLAB datetime arrays.
Fangjun Jiang
2023-12-19
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
2023-12-20
更多回答（2 个）
Fangjun Jiang
2023-12-19
编辑：Fangjun Jiang
2023-12-19
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
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)
类别
在 帮助中心 和 File Exchange 中查找有关 Dates and Time 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
