---
id: php-iterables
title: "PHP Iterables"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["Iterator interface", "PHP 이터러블"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.89
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["php", "programming", "w3schools", "iterables", "iterator"]
raw_sources: ["https://www.w3schools.com/php/php_iterables.asp"]
applied_in: []
github_commit: ""
---

# [[PHP Iterables]]

## 🎯 한 줄 통찰 (One-line insight)
The `iterable` type hint accepts EITHER a plain array OR any object implementing the `Iterator` interface — meaning a function declared `function printIterable(iterable $x)` works identically whether called with `["a","b","c"]` or a custom `MyIterator` object, since both satisfy the same "can be foreach'd" contract. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`iterable`** (PHP 7.1+) — a pseudo-type usable as a function parameter or return type; means "anything loopable with foreach." [S1]
- **Two things satisfy `iterable`** — any array, or any object implementing the `Iterator` interface. [S1]
- **`Iterator` interface — 5 required methods** — `current()` (return current element), `key()` (return current key — int/float/bool/string only), `next()` (advance pointer), `rewind()` (reset pointer to start), `valid()` (false if pointer is past the end). [S1]
- **Custom iterator pattern** — implement all 5 methods manually to make any custom class loopable via foreach. [S1]

## 📖 세부 내용 (Details)
- Iterable parameter accepting both array and iterator object: `function printIterable(iterable $x) { foreach($x as $item) { echo $item; } } printIterable(["a", "b", "c"]); $iterator = new ArrayIterator(["d", "e", "f"]); printIterable($iterator);`. [S1]
- Iterable return type: `function getIterable():iterable { return ["a", "b", "c"]; } foreach(getIterable() as $item) { echo $item; }`. [S1]
- Custom Iterator implementation: `class MyIterator implements Iterator { private $items = []; private $pointer = 0; public function __construct($items) { $this->items = array_values($items); } public function current() { return $this->items[$this->pointer]; } public function key() { return $this->pointer; } public function next() { $this->pointer++; } public function rewind() { $this->pointer = 0; } public function valid() { return $this->pointer < count($this->items); } }`. [S1]
- Using the custom iterator as an iterable: `$iterator = new MyIterator(["a", "b", "c"]); printIterable($iterator);`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
소스에서 모순되는 정보는 발견되지 않음.

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 배열과 커스텀 이터레이터 객체를 동일한 함수에 전달할 수 있는 것이 iterable 타입 힌트의 실전 가치다. [S1]

## 💻 코드 패턴 (Code patterns)
A function accepting both an array and an Iterator object via iterable (PHP):
```php
function printIterable(iterable $x) {
    foreach ($x as $item) {
        echo $item;
    }
}
printIterable(["a", "b", "c"]);           // array works
printIterable(new ArrayIterator(["d", "e", "f"])); // Iterator object works too
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.89
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[PHP Tutorial]]
- **관련 개념:** [[PHP Namespaces]], [[PHP MySQL Intro]], [[PHP Looping Foreach]]
- **참조 맥락:** 언어 핵심 문법의 마지막 챕터 — MySQL 연동 섹션으로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP Iterables — https://www.w3schools.com/php/php_iterables.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "PHP Iterables" page (Astra wiki-curation, P-Reinforce v3.1 format).
