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Date Vector/Number to ISO 8601 Date String

version 2.0.1 (18.2 KB) by Stephen Cobeldick
Convert a Date Vector/Number to an ISO 8601 Date String. Tokens control the date/time notation.


Updated 29 Nov 2020

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Easy conversion of a datetime or a date vector or a serial date number into a date string. The date string may be an ISO 8601 timestamp or a single date/time value, selected by (optional) input token/s. Multiple tokens may be used to output multiple strings.

The ISO 8601 timestamp style options supported by this function are:
* Date in calendar, ordinal, or week-numbering notation.
* Basic or extended format.
* Choice of date-time separator character.
* Full or lower precision (fewer trailing date/time units).
* Decimal fraction of the trailing unit (decimal places).

Does NOT parse or support timezones.

By default the function uses the current time and returns the basic ISO 8601 calendar timestamp: this is very useful for naming files that sort alphabetically into chronological order.

### Examples ###

* Using the date+time given by date vector [1999,1,3,15,6,48.0568].

>> datestr8601()
ans = '19990103T150648'

>> datestr8601([],'yn_HM')
ans = '1999003_1506'

>> datestr8601(clock,'*ymdHMS')
ans = '1999-01-03T15:06:48'

>> [D1,D3] = datestr8601(now-2,'D','DDD')
D1 = '5'
D3 = 'Fri'

>> datestr8601(datetime,'DDDD','d*','mmmm','yyyy')
ans = 'Sunday 3rd January 1999'

>> [da,YWD,mmyy] = datestr8601([],'d*','*YWD','mmmm','yyyy');
>> sprintf('The %s of %s has the ISO week-date "%s".',da,mmyy,YWD)
ans = 'The 3rd of January 1999 has the ISO week-date "1998-W53-7".'

### ISO 8601 Date Notations ###

Timestamps are shown here in extended format with the default date-time separator character 'T'.

1) Calendar:
string: '1999-01-03T15:06:48'
token: '*ymdHMS'

2) Ordinal:
string: '1999-003T15:06:48'
token: '*ynHMS'

3) Week-numbering:
string: '1998-W53-7T15:06:48'
token: '*YWDHMS'

### Single-Value Strings ###

* Consistent token syntax (UPPERCASE = week-numbering year, lowercase = calendar year).
* Easily adapted to other languages.
* Single-values include: day of the year or days remaining in year; year quarter (3-month or 13-week); year; month as digit or name; day of week as digit or name; date of month; hour; minute; second; deci/centi/milliseconds.

Cite As

Stephen Cobeldick (2021). Date Vector/Number to ISO 8601 Date String (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (7)

Timothy Miller

Thank you for providing a well written and documented piece of code. It is exactly what I needed.

Lautaro Parada


Stephen Cobeldick

@Tago: you seem to be trying to use DATESTR8601 as if it was MATLAB's inbuilt DATESTR. In actual fact DATESTR8601 is not the same function as the inbuilt DATESTR: they are different functions with different syntaxes and different documentation. You should try reading the DATESTR8601 documentation, as then you would know how to use it.

Both of your cases are easy to achieve:

>> datestr8601([],'ymdHMS3')
ans = 20181117T144652.899

>> datestr8601([],'ymd')
ans = 20181117



Sometimes simple to use, but not working fine. Simple requests like:
datestr8601([],'yyyy-mm-dd HH:MM:SS.FFF')
datestr8601([], 'yyyy-mm-dd');
Everything failed,


Thanks a lot. A very useful subroutine.

MATLAB Release Compatibility
Created with R2010b
Compatible with any release
Platform Compatibility
Windows macOS Linux

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