2nd/10_Wiki/Dev/Topic_PHP/PHP_Arrays_Multidimensional.md

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

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-arrays-multidimensional	PHP Arrays Multidimensional	Programming_Language	draft	conceptual		multidimensional arrays PHP 다차원 배열		B	0.9	2026-07-04	2026-07-04			php programming w3schools arrays multidimensional	https://www.w3schools.com/php/php_arrays_multidimensional.asp

PHP Arrays Multidimensional

🎯 한 줄 통찰 (One-line insight)

PHP explicitly warns that arrays nested more than THREE levels deep become "hard to manage for most people" — even though PHP technically supports arbitrary nesting depth, the tutorial itself sets a practical human-comprehension limit rather than a technical one. [S1]

🧠 핵심 개념 (Core concepts)

• Multidimensional array — an array containing one or more arrays. [S1]
• Two-dimensional array — an array of arrays, needing TWO indices (row, column) to reach an element. [S1]
• Dimension = index count — a 3D array needs 3 indices per element, and so on. [S1]
• Nested loops for traversal — a for inside a for, or foreach inside a foreach, to visit every cell. [S1]

📖 세부 내용 (Details)

• 2D array representing a table: $cars = array( array("Volvo", 22, 18), array("BMW", 15, 13), array("Saab", 5, 2), array("Land Rover", 17, 15) );. [S1]
• Element access with two indices: echo $cars[0][0].": In stock: ".$cars[0][1].", sold: ".$cars[0][2].".<br>";. [S1]
• Nested for loops: for ($row = 0; $row < 4; $row++) { for ($col = 0; $col < 3; $col++) { echo $cars[$row][$col]; } }. [S1]
• Nested foreach loops building an HTML table: foreach ($cars as $row) { foreach ($row as $cell) { echo "<td>" . $cell . "</td>"; } }. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 실용적 깊이 제한 경고: PHP는 다차원 배열을 기술적으로 무제한 지원하지만, 3단계 이상 중첩은 대부분 사람에게 관리하기 어렵다고 명시적으로 경고함. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 자동차 재고/판매 테이블을 2차원 배열로 표현하고 HTML 테이블로 렌더링하는 것이 대표 실전 사례다. [S1]

💻 코드 패턴 (Code patterns)

Nested foreach building an HTML table from a 2D array (PHP):

echo "<table>";
foreach ($cars as $row) {
    echo "<tr>";
    foreach ($row as $cell) {
        echo "<td>" . $cell . "</td>";
    }
    echo "</tr>";
}
echo "</table>";

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.90
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: PHP Tutorial
• 관련 개념: PHP Arrays Sort, PHP Arrays Functions, PHP Looping For
• 참조 맥락: 2차원 이상 배열 구조 — 배열 함수(Functions) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — PHP Multidimensional Arrays — https://www.w3schools.com/php/php_arrays_multidimensional.asp

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "PHP Multidimensional Arrays" page (Astra wiki-curation, P-Reinforce v3.1 format).