2nd/10_Wiki/Dev/Topic_PHP/PHP_Variables.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-variables	PHP Variables	Programming_Language	draft	conceptual		PHP 변수		B	0.9	2026-07-04	2026-07-04			php programming w3schools variables	https://www.w3schools.com/php/php_variables.asp

PHP Variables

🎯 한 줄 통찰 (One-line insight)

PHP has NO variable declaration command — a variable is created the instant you assign it a value ($x = 5;), unlike statically-declared languages; this is the source's explicit framing of what makes PHP "loosely typed" from the very first line of variable usage. [S1]

🧠 핵심 개념 (Core concepts)

• $ prefix — every variable name starts with $. [S1]
• Naming rules — starts with a letter or underscore (never a number); alphanumeric + underscore only; case-sensitive. [S1]
• No declaration keyword — a variable springs into existence at first assignment. [S1]
• Loosely typed — PHP infers the data type from the assigned value; no explicit type annotation needed. [S1]
• var_dump() — reveals both the data type and value of a variable. [S1]
• Multiple assignment — $x = $y = $z = "Fruit"; assigns the same value to several variables in one statement. [S1]
• Supported data types — string, int, float, bool, array, object, null, resource, mixed. [S1]

📖 세부 내용 (Details)

• Basic assignment: $x = 5; $y = "John";. [S1]
• Output with interpolation: $txt = "W3Schools.com"; echo "I love $txt!"; — equivalent to echo 'I love ' . $txt . '!';. [S1]
• Type inspection: var_dump(5); var_dump("John"); var_dump(3.14); var_dump(true); var_dump([2, 3, 56]); var_dump(NULL);. [S1]
• Multi-assignment: $x = $y = $z = "Fruit";. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — var_dump()로 변수의 실제 타입과 값을 확인하는 것이 디버깅의 표준 도구다. [S1]

💻 코드 패턴 (Code patterns)

Multi-variable assignment in one line (PHP):

$x = $y = $z = "Fruit";

✅ 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 Variables Scope, PHP Echo Print, PHP Data Types
• 참조 맥락: 변수 기초 문법 — 스코프(Scope)/데이터 타입 챕터로 확장.

📚 출처 (Sources)

• [S1] W3Schools — PHP Variables — https://www.w3schools.com/php/php_variables.asp

📝 변경 이력 (Change history)

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