---
id: python-scope
title: "Python Scope"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["LEGB rule", "nonlocal", "파이썬 스코프"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.9
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["python", "programming", "w3schools", "scope", "global", "nonlocal", "legb"]
raw_sources: ["https://www.w3schools.com/python/python_scope.asp"]
applied_in: []
github_commit: ""
---

# [[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):
```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).