Regex for ISO 8601 durations

Question

I need a regular expression to validate durations in the ISO 8601 duration format (with the exception of fractional parts which I don't need).

PnYnMnDTnHnMnS

PnW

Here is what I have:

^P(\d+Y)?(\d+M)?(\d+W)?(\d+D)?(T(\d+H)?(\d+M)?(\d+S)?)?$

The only problem is that the strings P and PT are allowed with this regex as all of the parts are "zero or one" ?.

There needs to be at least one component (date or time)
If there is a T then there needs to be a time component (H, M, or S)
If there is a T then there may or may not be any date components (Y, M, or D)
Overflow is allowed (e.g. P72H is mostly equivalent to P3D)

Acceptable inputs:

P1Y        // date component only
P2MT30M    // date and time components
PT6H       // time component only
P5W        // another date component

Unacceptable inputs:

P         // no components
PT        // no components
P3MT      // T specified but not time components

Right now the invalid strings are passing client-side validation but failing on the server-side because it's passed into DateInteval but I'd like to fail on the client side if possible. If everyone was using Chrome 40+ I could specify minlength='3' on the input element to help but that isn't the case unfortunately.

Wiktor Stribiżew · Accepted Answer · 2018-11-30 08:01:05Z

If you have almost all parts optional, but you want to make sure there is something else after P or T, you can make use of look-aheads:

^P(?=\d+[YMWD])(\d+Y)?(\d+M)?(\d+W)?(\d+D)?(T(?=\d+[HMS])(\d+H)?(\d+M)?(\d+S)?)?$
  ^^^^^^^^^^^^                               ^^^^^^^^^^^^

They require a sequence of digits followed by a letter from the specified set to appear right after the preceding pattern.

See demo

UPDATE

If P can be "empty", use

^P(?!$)(\d+Y)?(\d+M)?(\d+W)?(\d+D)?(T(?=\d+[HMS])(\d+H)?(\d+M)?(\d+S)?)?$

See another demo. Here, (?!$) makes sure the string is not equal to P, and there must be some other symbols on the right.

Or, as @UlugbekUmirov suggests, it is enough to just use T(?=\d) (since all the optional parts start with a digit):

^P(?!$)(\d+Y)?(\d+M)?(\d+W)?(\d+D)?(T(?=\d)(\d+H)?(\d+M)?(\d+S)?)?$

UPDATE 2

If the numbers can be both float or integers, add (?:\.\d+)? after each \d+. Here is an updated pattern from Update 1:

^P(?!$)(\d+(?:\.\d+)?Y)?(\d+(?:\.\d+)?M)?(\d+(?:\.\d+)?W)?(\d+(?:\.\d+)?D)?(T(?=\d)(\d+(?:\.\d+)?H)?(\d+(?:\.\d+)?M)?(\d+(?:\.\d+)?S)?)?$

Rafi · Accepted Answer · 2018-11-04 12:44:49Z

4

The answers above don't include the situation of a decimal fraction (see here for details). The decimal fraction can occur on the last element. The following regex includes decimal fraction:

^P(?!$)((\d+Y)|(\d+\.\d+Y$))?((\d+M)|(\d+\.\d+M$))?((\d+W)|(\d+\.\d+W$))?((\d+D)|(\d+\.\d+D$))?(T(?=\d)((\d+H)|(\d+\.\d+H$))?((\d+M)|(\d+\.\d+M$))?(\d+(\.\d+)?S)?)??$

See here for tests.

answered Nov 4, 2018 at 12:44

Rafi

2,5001 gold badge27 silver badges34 bronze badges

Comments

pltc · Accepted Answer · 2021-10-24 07:34:47Z

According to this message about ISO 8601-2:2019(en), a negative duration is expressed with a minus - sign before the P and it also seems that an explicit positive duration can be indicated with a plus + sign.

Useful to include [-+]? or (-|\+)? before P

Finally, That message also shows the following examples from ISO 8601-2:2019(en) indicating that each component of the duration can be negatively signed.

| EXAMPLE 7 '-P2M1D' is equivalent to 'P-2M-1D'.
| EXAMPLE 8 '-P5DT10H' is equivalent to 'P-5DT-10H'.

Adding [-+]? before digits in components and allowing -+ in the lookahead for T makes sense to be 8601-2 compliant

Pavel Husakouski · Accepted Answer · 2020-04-20 08:41:30Z

0

Answers above require additional post-processing. /^(-?)P(?=\d|T\d)(?:(\d+)Y)?(?:(\d+)M)?(?:(\d+)([DW]))?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+(?:\.\d+)?)S)?)?$/ An output:

["P2Y9M3DT12H31M8.001S", "", "2", "9", "3", "D", "12", "31", "8.001", index: 0, input: "P2Y9M3DT12H31M8.001S", groups: undefined]

answered Apr 20, 2020 at 8:41

Pavel Husakouski

1451 silver badge9 bronze badges

1 Comment

Vladimir Ulchenko Over a year ago

supports fractional part in seconds only

Tomerikoo · Accepted Answer · 2021-10-24 11:34:45Z

0

If you are searching for a regular expression containing a start date and duration, check this out:

^(\d{4}(-\d{2}(-\d{2})?(?!:))?(T\d{2}(:\d{2}(:\d{2})?(\.\d+)?)?)?(Z|([+,-]\d{2}(:\d{2})?))?)?P(([0-9]+([.,][0-9]*)?Y)?([0-9]+([.,][0-9]*)?M)?([0-9]+([.,][0-9]*)?D)?T?([0-9]+([.,][0-9]*)?H)?([0-9]+([.,][0-9]*)?M)?([0-9]+([.,][0-9]*)?S)?)|\d{4}-?(0[1-9]|11|12)-?(?:[0-2]\d|30|31)T((?:[0-1][0-9]|[2][0-3]):?(?:[0-5][0-9]):?(?:[0-5][0-9]|60)|2400|24:00)$

edited Oct 24, 2021 at 11:34

Tomerikoo

19.5k16 gold badges58 silver badges68 bronze badges

answered Jul 19, 2020 at 18:00

elias

11 bronze badge

Comments

Aura_Mancer · Accepted Answer · 2024-12-17 16:44:32Z

The answers above do not consider this:

That according to the standard [according to the standard in page 23][1], only the smallest component can have a decimal fraction.
Weeks are only allowed by themselves, and not mixed with any of the other values.
The standard admits both commas (,) and full stop (.) to express the decimal part.

This expression takes all of it into account:

^P(?!$)(?:(?:((?:\d+Y)|(?:\d+(?:\.|,)\d+Y$))?((?:\d+M)|(?:\d+(?:\.|,)\d+M$))?((?:\d+D)|(?:\d+(?:\.|,)\d+D$))?(T((?:\d+H)|(?:\d+(?:\.|,)\d+H$))?((?:\d+M)|(?:\d+(?:\.|,)\d+M$))?((?:\d+S)|(?:\d+(?:\.|,)\d+S$))?)?)|(?:\d+(?:(?:\.|,)\d+)?W))$

This expression does not take into account any other extensions to the ISO8601 standard, as the original question asked for, however it should be trivial to add them. [1]: https://web.archive.org/web/20210312212543/http://www.loc.gov/standards/datetime/iso-tc154-wg5_n0038_iso_wd_8601-1_2016-02-16.pdf

Pedro Andrade · Accepted Answer · 2025-01-29 12:15:36Z

0

You could use Zod for it:

import { z } from "zod";
const DurationSchema = z.string().duration()
DurationSchema.parse("P2W")

More information: https://zod.dev/?id=strings

answered Jan 29, 2025 at 12:15

Pedro Andrade

4,6521 gold badge28 silver badges27 bronze badges

1 Comment

AdrianHHH Over a year ago

Please edit this to explain how it answers the question. I don't see anything that takes the input required by the question and I don't see any regex as wanted by the question.

Collectives™ on Stack Overflow

Regex for ISO 8601 durations

7 Answers 7

Comments

Comments

Comments

1 Comment

Comments

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

Comments

Comments

Comments

1 Comment

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related