When working with PHP, you may need to construct a recurring date period from an ISO-8601 recurrence specification. This guide explains the operation, shows what its arguments mean, and uses three separate examples to make the result easier to understand.
DatePeriod::createFromISO8601String: ISO-8601 period specifications include a recurrence marker, start date and duration.
What Is DatePeriod::createFromISO8601String in PHP?
Construct a recurring date period from an ISO-8601 recurrence specification. ISO-8601 period specifications include a recurrence marker, start date and duration.
Syntax:
DatePeriod::createFromISO8601String(string $specification, int $options = 0): static
Parameters and return value: The signature above identifies the arguments and return type where the API has a single call. For topic guides, follow the sequence of calls in the examples. Always distinguish a returned value from an object or variable modified by reference.
Important: Invalid recurrence strings can throw. Confirm the meaning of recurrence counts and start-date inclusion.
Example 1: Basic Usage
This example introduces the operation with a short and predictable input.
<?php
$period = DatePeriod::createFromISO8601String("R3/2026-01-01T00:00:00Z/P1D");
foreach ($period as $date) {
echo $date->format("Y-m-d") . PHP_EOL;
}
Output:
2026-01-01
2026-01-02
2026-01-03
2026-01-04
The code focuses on the main operation. ISO-8601 period specifications include a recurrence marker, start date and duration.
Example 2: Another Case
Now compare a different input, locale, date, or option to see another part of the behavior.
<?php
$period = DatePeriod::createFromISO8601String("R2/2026-03-01T00:00:00Z/P1W");
foreach ($period as $date) {
echo $date->format("Y-m-d") . PHP_EOL;
}
Output:
2026-03-01
2026-03-08
2026-03-15
What changes? Invalid recurrence strings can throw. Confirm the meaning of recurrence counts and start-date inclusion.
Practical Example: Applying It in an Application
Use the following separate example as a starting point for a small application task. Check any extension or environment requirements below before running it.
<?php
$specification = "R3/2026-10-01T00:00:00Z/P1D";
$period = DatePeriod::createFromISO8601String($specification);
$dates = [];
foreach ($period as $date) {
$dates[] = $date->format("Y-m-d");
}
print_r($dates);
Output:
Array
(
[0] => 2026-10-01
[1] => 2026-10-02
[2] => 2026-10-03
[3] => 2026-10-04
)
The practical example demonstrates how to apply this operation to multiple values, a reusable task, or a validated input. ISO-8601 period specifications include a recurrence marker, start date and duration.
Important Behavior and Edge Cases
- Core behavior: ISO-8601 period specifications include a recurrence marker, start date and duration.
- Inputs and results: Invalid recurrence strings can throw. Confirm the meaning of recurrence counts and start-date inclusion.
- Alternatives: new DatePeriod($start, $interval, $end) builds a period from date objects.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
DatePeriod::createFromISO8601String | Construct a recurring date period from an iso-8601 recurrence specification. |
| Related PHP approach | new DatePeriod($start, $interval, $end) builds a period from date objects. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Using an incorrect input or option | Invalid recurrence strings can throw. Confirm the meaning of recurrence counts and start-date inclusion. |
| Confusing this API with a related operation | new DatePeriod($start, $interval, $end) builds a period from date objects. |
| Assuming output is identical across environments | Check return values and required extensions or versions. Use explicit locale, timezone or encoding settings when they affect the result. |
Key Takeaways
- DatePeriod::createFromISO8601String helps you construct a recurring date period from an ISO-8601 recurrence specification.
- ISO-8601 period specifications include a recurrence marker, start date and duration.
- Invalid recurrence strings can throw. Confirm the meaning of recurrence counts and start-date inclusion.
Use DatePeriod::createFromISO8601String when you need to construct a recurring date period from an ISO-8601 recurrence specification. Start with the first example, compare the second, and adapt the practical example to your inputs. Confirm the return value and environment requirements before adding it to production code.