2nd/10_Wiki/Topics/Domain_Programming/Topic_PHP/PHP_Iterables.md

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

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):

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).