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Topic_CSS/Topic_HTML/Topic_JavaScript/Topic_Prompt/Topic_Comfyui 등 기존 카테고리 폴더를 정리하고, Topic_Graphic/Dev 등 신규 산출물과 Topics 내부 세션/메모리 기록을 동기화.
71 lines
2.8 KiB
Markdown
71 lines
2.8 KiB
Markdown
---
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id: python-none
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title: "Python None"
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category: "Programming_Language"
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status: "draft"
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verification_status: "conceptual"
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canonical_id: ""
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aliases: ["NoneType", "파이썬 None"]
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duplicate_of: ""
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source_trust_level: "B"
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confidence_score: 0.9
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created_at: 2026-07-04
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updated_at: 2026-07-04
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review_reason: ""
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merge_history: []
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tags: ["python", "programming", "w3schools", "none", "nonetype"]
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raw_sources: ["https://www.w3schools.com/python/python_none.asp"]
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applied_in: []
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github_commit: ""
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---
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# [[Python None]]
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## 🎯 한 줄 통찰 (One-line insight)
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None is the sole instance of its own type (NoneType), evaluates to False in a boolean context, and should be compared with `is`/`is not` (identity) rather than `==`/`!=` (equality). [S1]
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## 🧠 핵심 개념 (Core concepts)
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- **`None`** — a special constant representing the absence of a value; data type `NoneType`. [S1]
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- **Single instance** — None is the only instance of NoneType. [S1]
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- **Comparison** — use `is` / `is not`, not `==`/`!=`, to check for None. [S1]
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- **Falsy** — `bool(None)` is False. [S1]
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- **Default function return** — a function with no explicit `return` returns None. [S1]
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## 📖 세부 내용 (Details)
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- Assign and check type: `x = None; print(type(x)) # <class 'NoneType'>`. [S1]
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- Identity comparison: `if result is None: print("No result yet") else: print("Result is ready")`. [S1]
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- Truthiness: `print(bool(None)) # False`. [S1]
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- Implicit None return: `def myfunc(): x = 5; x = myfunc(); print(x) # None`. [S1]
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## ⚖️ 모순 및 업데이트 (Contradictions & updates)
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소스에서 모순되는 정보는 발견되지 않음.
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## 🛠️ 적용 사례 (Applied in summary)
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현재 발견된 실제 적용 사례가 없습니다 — Python Functions 챕터에서 이미 예고된 "return 없으면 None"이 여기서 정식으로 다뤄진다. [S1]
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## 💻 코드 패턴 (Code patterns)
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Identity comparison with None (Python):
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```python
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result = None
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if result is None:
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print("No result yet")
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```
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## ✅ 검증 상태 및 신뢰도
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- **상태:** draft
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- **검증 단계:** conceptual
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- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
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- **신뢰 점수:** 0.90
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- **중복 검사 결과:** 신규 생성 (New discovery)
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## 🔗 지식 그래프 (Knowledge Graph)
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- **상위/루트:** [[Python Tutorial]]
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- **관련 개념:** [[Python Functions]], [[Python Operators Identity]], [[Python Booleans]]
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- **참조 맥락:** "값 없음"을 표현하는 표준 상수 — is/is not 비교 규칙이 핵심.
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## 📚 출처 (Sources)
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- [S1] W3Schools — Python None — https://www.w3schools.com/python/python_none.asp
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## 📝 변경 이력 (Change history)
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- 2026-07-04: Initial draft synthesized from the W3Schools "Python None" page (Astra wiki-curation, P-Reinforce v3.1 format).
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