After a data export I get a string variable with "2017/02/22 1320:35 +000 4".
Through:
compute #TS = char.index(Timestamp_1, " ").
string date (A10).
compute date = char.substr(Timestamp_1,1,#TS).
alter type date (A10 = SDATE10).
I manage to get the date in a separate variable.
The same:
string time (A8).
compute time = char.substr(Timestamp_2,#TS+1,7).
alter type time (A8 = TIME8).
doesn't work for the time because it is in the 'hhmm:ss' format. How do I change the string variable '1320:35' into a time variable '13:20:35'?
You can insert a ":" manually into the time string by using the concat function before you alter the type.
COMPUTE time = CONCAT(CHAR.SUBSTR(time,1,2),":",(CHAR.SUBSTR(time,3))).
Another approach would be to extract hours, minutes and seconds from Timestamp variable individually and to use these elements inside the TIME.HMS function:
COMPUTE #hh = NUMBER(CHAR.SUBSTR(Timestamp_1,TS+1,2),F2).
COMPUTE #mm = NUMBER(CHAR.SUBSTR(Timestamp_1,TS+3,2),F2).
COMPUTE #ss = NUMBER(CHAR.SUBSTR(Timestamp_1,TS+6,2),F2).
COMPUTE time = TIME.HMS(#hh,#mm,#ss).
EXECUTE.
FORMATS time (TIME8).
Statistics has a datetime format and, new in V24, an ISO 8601 timestamp format, YMDHMS. If the string is converted to a regular date/time value, then the XDATE.DATE and XDATE.TIME functions can be used to extract the pieces. The Date and Time wizard may accommodate the format you have (not sure about that +000 4 part at the end).
Related
I have a time series data recorded in different time zones (sample figure attached). Please note that the time information is in UTC. I need to convert them to local time (AM/PM) automatically for a large dataset. I have attached sample data and any help in this regard is highly appreciated.
https://www.dropbox.com/s/i2eeja8a7em87v9/Sample.csv?dl=0
You can use the TimeZone property for MATLAB's datetime data type to do the conversion for you. The only complication is then getting MATLAB to "forget" the timezone info so that you can just have a simple dataset with your desired datetimes. I've achieved this going via datenum below:
Note that if you want to retain the timezone information then you can simplify this by not doing the extra conversion steps.
Note also you would replace my dummy data at the top with readtable or similar to bring in the data, but I've assumed that the source data is entirely cells of chars, i.e. you may need to be careful of readtable "cleverly" detecting a datetime column, this may mean you have to handle it differently in the loop or provide additional arguments to readtable to prevent this automation.
data = cell2table( { ...
'4/02/2021 16:25', 'Pacific/Auckland'
'4/02/2021 16:05', 'Pacific/Auckland'
'5/02/2021 9:17', 'America/Chicago'
'4/02/2021 22:27', 'Asia/Singapore'
}, 'VariableNames', {'timeStrUtc','timezone'} );
data.timeUtc(:) = NaT;
data.timeLocal(:) = NaT;
for ii = 1:height(data)
% Convert input string to UTC-timezoned datetime
zonedDateUtc = datetime( data.timeStrUtc{ii}, ...
'InputFormat', 'dd/MM/yyyy HH:mm', ...
'TimeZone', 'UTC' );
% Convert to a local datetime
zonedDateLocal = datetime( zonedDateUtc, 'TimeZone', data.timezone{ii} );
% Get rid of MATLAB's associated timezones by converting to datenum
zonedDateUtc = datenum( zonedDateUtc );
zonedDateLocal = datenum( zonedDateLocal );
% Assign output to table, without timezones so all utc/local
data.timeUtc(ii) = datetime( zonedDateUtc, 'ConvertFrom', 'datenum' );
data.timeLocal(ii) = datetime( zonedDateLocal, 'ConvertFrom', 'datenum' );
end
% Format table columns
data.timeUtc.Format = 'd/M/yyyy h:mm a';
data.timeLocal.Format = 'd/M/yyyy h:mm a';
You can do this using a combination of readtable and the datetime constructor. First use readtable to read the data as text (because we want more control over the datetime construction):
t = readtable('Sample.csv', 'DateTimeType', 'text', 'TextType', 'string');
This results in a Nx2 table with string data. To convert each row to a datetime, we need a form of the datetime constructor like this:
datetime("4/02/2021 16:25", "InputFormat", "MM/dd/uuuu HH:mm", "TimeZone", "UTC")
Please check the "InputFormat" used there, because it isn't entirely obvious whether you want "MM/dd/uuuu" or "dd/MM/uuuu".
We can add another variable to the table t like this:
% Make a UTC datetime
t.endTimeUtc = datetime(t.endTimeUtcSecs, 'InputFormat', 'MM/dd/uuuu HH:mm', 'TimeZone', 'UTC');
Next, we need to convert each datetime from being in UTC to being in the specified TimeZone. Because a datetime array has a single TimeZone for the entire array, we must create a cell array of results. So, here's a function that takes a datetime and a time zone, and returns a new datetime wrapped in a cell array.
fun = #(ts, z) {datetime(ts, 'TimeZone', z, 'Format', 'MM/dd/uuuu HH:mm Z')};
(That function also sets up the display format of the datetime array to include time zone information)
We want to apply that function to the new variable in the table, and the time zone variable. Like this:
zonedEndTime = rowfun(fun, t(:, {'endTimeUtc', 'recordingTimezone'}));
(Note that I got a few warnings because some of your TimeZone specifications are apparently ambiguous)
This gives me the following result:
>> head(zonedEndTime)
ans =
8×1 table
Var1
__________________________
{[04/03/2021 05:25 +1300]}
{[04/03/2021 05:05 +1300]}
{[05/02/2021 04:17 -0500]}
{[04/03/2021 06:27 +0800]}
{[05/02/2021 01:51 -0500]}
{[05/02/2021 07:42 +0200]}
{[05/02/2021 08:17 +0800]}
{[05/02/2021 01:22 -0400]}
Im trying to convert the first two columns of a cell into a Matlab time. First column {1,1} is the date in YYYY-MM-DD format and the second is the time in HH:MM format.
Any ideas where I'm going wrong? My code:
file = 'D:\Beach Erosion and Recovery\Bournemouth\Bournemouth Tidal
Data\tidal_data_jtide.txt'
fileID = fopen(file);
LT_celldata = textscan(fileID,'%D%D%D%D%d%[^\n\r]','delimiter',',');
formattime = 'yyyy-mm-dd HH:MM'
date = LT_celldata{1,1};
time = LT_celldata{1,2};
date_time = datenum('date','time'); code
Screenshot below is LT_celldata{1,1} :
You can combine variables date and time with the following code:
date = datetime(LT_celldata{1,1},'InputFormat','yyyy-MM-dd');
time = datetime(LT_celldata{1,2},'InputFormat','HH:mm:ss','Format','HH:mm:ss');
myDatetime = datetime(date + timeofday(time),'Format','yyyy-MM-dd HH:mm:ss');
The code uses timeofday function to combine date and time information from the two different variables. You may find more information and examples at this documentation page.
Is there a method in matlab to convert seconds from a known date to a standard date time format?
For example, if I have a vector of values shown as seconds from 1901/01/01, how would I convert them to a dateTime? In this case a value of 28125 would correspond to 1981/01/01. Is there an efficient method for doing this?
The numbers in your example do not make sense so it is not clear if your time is in seconds or days but since you asked for seconds I will use this.
What you want to achieve can be done using datenum function. This function returns the number of (fractional) days from 1/1/0000. So first you need to find your offset, e.g.:
offsetInDays = datenum(1901,1,1);
Next, you convert the date from seconds to days:
dateInDays = YourRequiredDateInSec * 3600 * 24;
Finally, you date is given by
RequiredDate = datestr(offsetInDays + dateInDays);
I'm trying to compare a file's modified date with a specific date.
What I have is this:
If FormatDateTime(objFile.DateLastModified,vbShortDate) = specificDate Then
'Do something
End if
I've tried using IsDate and a variable with a value of #11/9/2015# but always returns false. I can't figure out how to set the variable "specificDate" to 11/9/2015.
If you are comparing the date only (but not the time), then you have to cut off the fractional part of the last modified value, since integer part represents days, and fractional part - hours, minutes and seconds. After any changes convert the values back to Date type with CDate(), as well as date containing string before the comparison.
Sub Test()
dtSpecificDate = CDate("11/9/2015")
With CreateObject("Scripting.FileSystemObject").GetFile("C:\Test\tmp.txt")
dtLastModified = CDate(Int(.DateLastModified))
End With
If dtLastModified = dtSpecificDate Then
' Do something
End If
End Sub
I need to convert date and time into a numerical value. for example:
>> num = datenum('2011-05-07 11:52:23')
num =
7.3463e+05
How would I write a script to do this for numerous values without inputting the date and time manually?
You can store your date strings first in a cell array (or a matrix, provided they are of fixed format), and feed it straight to datenum. For example:
C = {'2011-05-07 11:52:23'
'2011-03-01 20:30:01'};
vals = datenum(C)