Oihana PHP Standards

isIso8601Interval.php

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Functions

isIso8601Interval()  : bool
Validates whether a string is a valid ISO 8601 time interval.

Functions

isIso8601Interval()

Validates whether a string is a valid ISO 8601 time interval.

isIso8601Interval(string $value) : bool

An interval is two ISO 8601 expressions joined by a / separator, in one of the following forms:

  • <start>/<end> — two strict date-times (e.g. 2026-05-14T00:00:00Z/2026-05-15T00:00:00Z)
  • <start>/<duration> — a start date-time and a duration (e.g. 2026-05-14T00:00:00Z/P1D)
  • <duration>/<end> — a duration and an end date-time (e.g. P1D/2026-05-15T00:00:00Z)

The single-<duration> short form (e.g. P1D alone) is intentionally rejected: use Iso8601Duration for that case. Open intervals (--/<end> and <start>/-- from ISO 8601:2019) are also rejected for now.

Date-time components are validated in strict mode (mandatory T separator).

Parameters
$value : string

The interval string to validate

Tags
example 
isIso8601Interval('2026-05-14T00:00:00Z/2026-05-15T00:00:00Z'); // true
isIso8601Interval('2026-05-14T00:00:00Z/P1D');                  // true
isIso8601Interval('P1D/2026-05-15T00:00:00Z');                  // true
isIso8601Interval('P1D');                                        // false (use Iso8601Duration)
isIso8601Interval('P1D/P2D');                                    // false (two durations)
isIso8601Interval('--/2026-05-15T00:00:00Z');                    // false (open interval)
link

ISO 8601 Time intervals
author

Marc Alcaraz (ekameleon)

since
1.0.2
Return values
bool —

True if the string is a valid ISO 8601 interval, false otherwise

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