2nd/10_Wiki/Topics/Domain_Programming/Topic_PHP/PHP_Switch.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-switch	PHP Switch	Programming_Language	draft	conceptual		PHP 스위치문		B	0.9	2026-07-04	2026-07-04			php programming w3schools switch	https://www.w3schools.com/php/php_switch.asp

PHP Switch

🎯 한 줄 통찰 (One-line insight)

Omitting break causes "fall-through" that runs the NEXT case's code too, regardless of whether it matches — the source's own example demonstrates this directly: removing break from the matched "red" case makes the "blue" case's code execute right after it, even though $favcolor is definitely not "blue". [S1]

🧠 핵심 개념 (Core concepts)

• switch(expression) — evaluates once, compares against each case. [S1]
• break — required to stop fall-through into the next case; the LAST case doesn't strictly need it. [S1]
• Fall-through warning — omitting break in a non-last case runs the next case's code unconditionally. [S1]
• default — runs when no case matches. [S1]
• Combining cases — stacking multiple case labels with no code between them shares one code block. [S1]

📖 세부 내용 (Details)

• Basic switch: switch ($favcolor) { case "red": echo "Your favorite color is red!"; break; case "blue": ...; default: ...; }. [S1]
• Fall-through demonstration: removing break from case "red": causes case "blue":'s code to also run even though favcolor is "red", not "blue". [S1]
• Combined cases: case 1: case 2: case 3: case 4: case 5: echo "The week feels so long!"; break; case 6: case 0: echo "Weekends are best!"; break;. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• break 생략 시 폴스루(fall-through) 경고: 마지막이 아닌 case에서 break를 생략하면 다음 case 코드가 매치 여부와 무관하게 실행된다는 점이 예제로 직접 증명됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 요일 그룹(평일/주말)을 case 결합으로 표현하는 것이 실전 활용의 대표 패턴이다. [S1]

💻 코드 패턴 (Code patterns)

Combining multiple case labels for shared logic (PHP):

$d = 3;
switch ($d) {
    case 1:
    case 2:
    case 3:
    case 4:
    case 5:
        echo "The week feels so long!";
        break;
    case 6:
    case 0:
        echo "Weekends are best!";
        break;
    default:
        echo "Something went wrong";
}

✅ 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 If Nested, PHP Match, PHP Looping
• 참조 맥락: 다중 분기 구조 — Match 표현식(PHP 8) 챕터로 직접 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — PHP switch Statement — https://www.w3schools.com/php/php_switch.asp

📝 변경 이력 (Change history)

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