---
id: python-else
title: "Python Else"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["Python Else Statement", "파이썬 else"]
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", "else", "conditions"]
raw_sources: ["https://www.w3schools.com/python/python_if_else.asp"]
applied_in: []
github_commit: ""
---

# [[Python Else]]

## 🎯 한 줄 통찰 (One-line insight)
else is the fallback that catches everything not matched by preceding if/elif conditions, and it must always come last — Python doesn't allow an elif after an else. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`else`** — catches anything not caught by preceding if/elif conditions. [S1]
- **Must come last** — no elif can follow an else. [S1]
- **Works with or without elif** — a simple `if/else` two-way branch is valid on its own. [S1]
- **Common uses** — error handling, validation, providing default values. [S1]

## 📖 세부 내용 (Details)
- With elif: `if b > a: ... elif a == b: ... else: print("a is greater than b")`. [S1]
- Without elif (simple two-way): `if b > a: ... else: print("b is not greater than a")`. [S1]
- Even/odd check: `if number % 2 == 0: "even" else: "odd"`. [S1]
- Validation fallback: `if len(username) > 0: print(f"Welcome, {username}!") else: print("Error: Username cannot be empty")`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
소스에서 모순되는 정보는 발견되지 않음.

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 입력 검증/기본값 제공처럼 "그 외 모든 경우"를 처리하는 표준 패턴이다. [S1]

## 💻 코드 패턴 (Code patterns)
Fallback validation pattern (Python):
```python
username = "Emil"
if len(username) > 0:
    print(f"Welcome, {username}!")
else:
    print("Error: Username cannot be empty")
```

## ✅ 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 Elif]], [[Python If Shorthand]]
- **참조 맥락:** if/elif 체인의 기본 폴백 — 유효성 검사/기본값 제공에 표준적으로 사용.

## 📚 출처 (Sources)
- [S1] W3Schools — Python Else Statement — https://www.w3schools.com/python/python_if_else.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "Python Else Statement" page (Astra wiki-curation, P-Reinforce v3.1 format).
