2nd/10_Wiki/Topics/Domain_Programming/Topic_Python/Python_Scope.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
python-scope	Python Scope	Programming_Language	draft	conceptual		LEGB rule nonlocal 파이썬 스코프		B	0.9	2026-07-04	2026-07-04			python programming w3schools scope global nonlocal legb	https://www.w3schools.com/python/python_scope.asp

Python Scope

🎯 한 줄 통찰 (One-line insight)

Python resolves a variable name by searching Local → Enclosing → Global → Built-in scopes in that order (the LEGB rule), and global/nonlocal are the two keywords that let inner code write to an outer scope instead of shadowing it. [S1]

🧠 핵심 개념 (Core concepts)

• Scope — the region where a variable is accessible. [S1]
• Local scope — a variable created inside a function is only usable inside that function (and functions nested within it). [S1]
• Global scope — a variable created at the top level of a module is usable everywhere. [S1]
• Same-name shadowing — a local variable with the same name as a global one is treated as a SEPARATE variable — the local one shadows the global inside the function, without affecting the global. [S1]
• global keyword — lets a function create or modify a variable in the global scope. [S1]
• nonlocal keyword — lets a nested function modify a variable belonging to its enclosing (outer) function, not the module-level global scope. [S1]
• LEGB rule — name resolution order: Local → Enclosing → Global → Built-in. [S1]

🧩 추출된 패턴 (Extracted patterns)

• global vs nonlocal target different levels — global reaches all the way to module scope; nonlocal reaches only the nearest enclosing FUNCTION scope, not the module — picking the wrong one is a common source of SyntaxError or silent shadowing. [S1]

📖 세부 내용 (Details)

• Local scope: def myfunc(): x = 300; print(x) — x unavailable outside. [S1]
• Global scope: x = 300; def myfunc(): print(x); myfunc(); print(x). [S1]
• Shadowing: x = 300; def myfunc(): x = 200; print(x); myfunc(); print(x) — prints 200 then 300. [S1]
• global to modify: def myfunc(): global x; x = 200; myfunc(); print(x). [S1]
• nonlocal to modify enclosing scope: def myfunc1(): x = "Jane"; def myfunc2(): nonlocal x; x = "hello"; myfunc2(); return x. [S1]
• LEGB demonstration: nested outer()/inner() each define x; each print shows the scope-appropriate value. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — Decorators 챕터의 클로저(inner function이 outer function의 변수를 참조하는 패턴)가 이 Enclosing 스코프 개념에 직접 의존한다. [S1]

💻 코드 패턴 (Code patterns)

nonlocal modifies the enclosing function's variable (Python):

def myfunc1():
    x = "Jane"
    def myfunc2():
        nonlocal x
        x = "hello"
    myfunc2()
    return x

print(myfunc1())  # hello

✅ 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: Python Tutorial
• 관련 개념: Python Global Variables, Python Decorators, Python Lambda
• 참조 맥락: 변수 이름 해석 규칙(LEGB)의 기초 — 데코레이터/클로저 이해에 필수.

📚 출처 (Sources)

• [S1] W3Schools — Python Scope — https://www.w3schools.com/python/python_scope.asp

📝 변경 이력 (Change history)

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