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10_Wiki/Topic_Programming/Topic_Python/Python_Elif.md

@@ -0,0 +1,77 @@
+---
+id: python-elif
+title: "Python Elif"
+category: "Programming_Language"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["Python Elif Statement", "파이썬 elif"]
+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", "elif", "conditions"]
+raw_sources: ["https://www.w3schools.com/python/python_if_elif.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[Python Elif]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+`elif` checks conditions top-to-bottom and stops at the FIRST true one — so even if multiple conditions would be true, only the first matching block executes, making elif chains cheaper than separate independent if statements. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **`elif`** — "if the previous conditions were not true, then try this condition". [S1]
+- **Multiple elif** — as many as needed; Python checks each in order. [S1]
+- **First-match-wins** — execution stops at the first true condition, even if later ones would also be true. [S1]
+- **When to use** — for multiple mutually exclusive conditions; more efficient than separate if statements since checking stops early. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Mutual-exclusivity assumption** — elif chains are designed for conditions that are logically exclusive (e.g. grade bands); using elif for conditions that could overlap silently discards all but the first match. [S1]
+
+## 📖 세부 내용 (Details)
+- Basic elif: `if b > a: ... elif a == b: print("a and b are equal")`. [S1]
+- Grade band chain: `if score >= 90: "A" elif score >= 80: "B" elif score >= 70: "C" elif score >= 60: "D"` — score 75 prints "C" only. [S1]
+- Day-of-week chain: 7 elif branches, one per day number. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+소스에서 모순되는 정보는 발견되지 않음.
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — 등급 분류, 요일 판별처럼 상호 배타적인 다중 조건 로직의 표준 패턴이다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+First-match-wins elif chain (Python):
+```python
+score = 75
+if score >= 90:
+    print("Grade: A")
+elif score >= 80:
+    print("Grade: B")
+elif score >= 70:
+    print("Grade: C")  # this one executes
+elif score >= 60:
+    print("Grade: D")
+```
+
+## ✅ 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 If Statement]], [[Python Else]], [[Python Match]]
+- **참조 맥락:** 상호 배타적 다중 조건 분기 — Match 문(3.10+)의 대안으로도 비교된다.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — Python Elif Statement — https://www.w3schools.com/python/python_if_elif.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "Python Elif Statement" page (Astra wiki-curation, P-Reinforce v3.1 format).