The Traversable interface

(PHP 5, PHP 7, PHP 8)

Introduction

Interface to detect if a class is traversable using foreach.

Abstract base interface that cannot be implemented alone. Instead, it must be implemented by either IteratorAggregate or Iterator.

Interface synopsis

interface Traversable {
}

This interface has no methods, its only purpose is to be the base interface for all traversable classes.

Changelog

VersionDescription
7.4.0The Traversable interface can now be implemented by abstract classes. Extending classes must implement Iterator or IteratorAggregate.

Notes

Note:

Internal (built-in) classes that implement this interface can be used in a foreach construct and do not need to implement IteratorAggregate or Iterator.

Note:

Prior to PHP 7.4.0, this internal engine interface couldn't be implemented in PHP scripts. Either IteratorAggregate or Iterator must be used instead.