How do I convert this string to a date ?

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Jules PASCO 2021-5-26

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评论： Jules PASCO 2021-6-2

Hi everybody !

I'm trying to turn this string to a date (from a txt file): 2021-05-11T14:11:00Z to 'yyyy-MM-dd HH:mm:ss'.

I tried with datetime(ref_time(h, 1),'InputFormat', 'yyyy-MM-dd e HH:mm:ss e','Format','yyyy-MM-dd HH:mm:ss') with an 'e' replacing the 'T' and 'Z' but id doesn't work...

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Answer 1

Asmit Singh 2021-5-26

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Since you are trying to convert strings to date with literals like 'T' and 'Z', you may want to look at the "Date and Time from Text with Literal Characters" section in the documentation.

The below code converts the given string format to matlab datetime variable.

myDate = "2021-05-11T14:11:10Z"
datetime(myDate,'InputFormat','yyyy-MM-dd''T''HH:mm:ss''Z')

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Stephen23 2021-6-1

编辑：Stephen23 2021-6-1

@Jules PASCO: Of course it will not work: does the "InputFormat" match the input data format? (hint: no)

This is what you are telling MATLAB (and us in your question) that your dates looks like:

'yyyy-MM-dd e HH:mm:ss e'

whereas this is (apparently) what your dates actually look like:

'04-May-2021 11:00:00'

Are they the same format? (hint: no)

"The only problem is that I can't turn this format into a datetime, it stays a string."

It works for me:

S = '04-May-2021 11:00:00';
T = datetime(S, 'InputFormat','dd-MMM-yyyy HH:mm:ss') % !!! DATETIME !!!
T = datetime
   04-May-2021 11:00:00
T.Format = 'yyyy-MM-dd HH:mm:ss' % !!! Still DATETIME !!!
T = datetime
   2021-05-04 11:00:00

Did you specify the InputFormat to actually match the data you have?

Jules PASCO 2021-6-2

Ok! It works now!

To make the dates match the values, I imported my data files as arrays instead of vectors/matrices like before, but I have the impression that matlab differentiates arrays from matrices, which prevents me from doing the date conversion...

If I can't do it any other way I'd switch my array to matrix but the point of array is that it recognizes dates.

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Answer 2

Allen 2021-5-26

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Try running a string replacement to remove "T" and "Z" from your string before reformatting to datetime.

str = "2021-05-11T14:11:00Z";
datetime(regexprep(str,["T","Z"],[" ",""]))
ans = datetime
   11-May-2021 14:11:00

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Stephen23 2021-5-26

The "T" is specified in ISO 8601, it would be a very unfortunate if DATETIME could not handle it:

https://en.wikipedia.org/wiki/ISO_8601

The "Z" refers to the Zulu time zone:

https://en.wikipedia.org/wiki/List_of_military_time_zones

and as such it conveys important information which cannot be disregarded:

S = '2021-05-11T14:11:00Z';
T = datetime(S,'InputFormat','yyyy-MM-dd''T''HH:mm:ssZ', 'TimeZone','UTC')
T = datetime
   11-May-2021 14:11:00
T.TimeZone = 'Asia/Shanghai'
T = datetime
   11-May-2021 22:11:00