Timestamp in ISO 8601 to yyyy-MM-dd HH:mm:ss

Question

Ercan 2022-10-11

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1822898-timestamp-in-iso-8601-to-yyyy-mm-dd-hh-mm-ss

评论： dpb 2022-10-12

采纳的回答： dpb

Hey there!

I am trying to parse the ISO8601 timestamp into readible format like 'yyyy-MM-dd HH:mm:ss'

However, no matter how hard I try, I couldn't be able to do the conversion.

I keep getting the message which reads "

>>> datetime('0000-00-00T14:26:21:000','InputFormat','yyyy-MM-dd''T''HH:mm:ss')

Error using datetime

Unable to convert '0000-00-00T14:26:21:000' to datetime using the format 'yyyy-MM-dd'T'HH:mm:ss'.

Can anyone please tell me what I am doing incorrectly in the syntax ?

5 个评论
显示 3更早的评论隐藏 3更早的评论

Stephen23 2022-10-11

Building on dpb's comment: given that all date units are zero, perhaps a DURATION object would be more suitable.

Do any of the timestamps have non-zero date units? What is the range of expected times/dates?

Ercan 2022-10-11

All of the timestamps have zero date units. But this is not important for my project. I just need to convert the time after "T" to a plottable time value. At this moment MATLAB won't allow me to plot the time against, say pressure.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

dpb 2022-10-12

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1822898-timestamp-in-iso-8601-to-yyyy-mm-dd-hh-mm-ss#answer_1071978

编辑：dpb 2022-10-12

在 MATLAB Online 中打开

It's a pit(proverbial)a(ppendage) when vendor code produces nonstandard formats...

S='0000-00-00T14:26:21:000';        % sample date string
datetime(extractAfter(S,'T'),'InputFormat','HH:mm:ss:SSS','Format',"HH:mm:ss.SSS")
ans = datetime
   14:26:21.000

converts the time portion with the behavior of datetime with a missing date to default to the current date.

Unfortunately, the limitations of what TMW has implemented for the duration class formats wipes out that as an alternative...

duration(extractAfter(S,'T'),'InputFormat','hh:mm:ss:SSS')
Error using duration
Unsupported format 'hh:mm:ss:SSS'. See the documentation of 'InputFormat' for valid formats.

datetime is more forgiving in letting the additional ":" pass when given as part of the format string; for some reason the developers didn't provide duration the same level of customization.

2 个评论
显示无隐藏无

Ercan 2022-10-12

I can't thank you enough, to be honest. Saved my day.

dpb 2022-10-12

在 MATLAB Online 中打开

Here's where timeofday has its use, too...

S='0000-00-00T14:26:21:000';        % sample date string
timeofday(datetime(extractAfter(S,'T'),'InputFormat','HH:mm:ss:SSS'))
ans = duration
   14:26:21

returns a duration to wipe out the funky date portion.

请先登录，再进行评论。

Answer 2

Cris LaPierre 2022-10-12

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1822898-timestamp-in-iso-8601-to-yyyy-mm-dd-hh-mm-ss#answer_1071993

编辑：Cris LaPierre 2022-10-12

I would follow this example: Date and Time from Text with Literal Characters

DateStrings = {'2014-05-26T13:30-05:00';'2014-08-26T13:30-04:00';'2014-09-26T13:30Z'}

t = datetime(DateStrings,'InputFormat','uuuu-MM-dd''T''HH:mmXXX','TimeZone','UTC')

Your data is returning an error because the month-day data are zeros, which violates the ISO8601 date format spec:

[MM] indicates a two-digit month of the year, 01 through 12.
[DD] indicates a two-digit day of that month, 01 through 31.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Cris LaPierre 2022-10-12

在 MATLAB Online 中打开

Me either. I think your answer is the best you can do.

XXX is for capturing timezone (in the example, the timezone is in the format -5:00), but the OP's data does not have timezone. In that case, your first option is the correct approach.

t=timeofday(datetime('0000-00-00T14:26:21:000','InputFormat','''0000-00-00T''HH:mm:ss:SSS'))
t = duration
   14:26:21

Main point - this is not an ISO 8601 date. If it were, datetime could import it.

dpb 2022-10-12

OK, thanks...I misinterpreted your "I would follow..." as saying it should work somehow.

I always forget about the "XXX" being part of the formatting string set; the doc for datetime is pretty disjointed in that it takes several jumps to get to the full table of possible formatting strings from the abbreviated list at the input description don't always go there.

请先登录，再进行评论。