---
id: python-variables
title: "Python Variables"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["파이썬 변수"]
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", "variables"]
raw_sources: ["https://www.w3schools.com/python/python_variables.asp"]
applied_in: []
github_commit: ""
---

# [[Python Variables]]

## 🎯 한 줄 통찰 (One-line insight)
Python variables need no declaration or fixed type — a variable is created on first assignment and can be reassigned to a completely different type later, with `type()` always available to check its current type. [S1]

## 🧠 핵심 개념 (Core concepts)
- **No declaration keyword** — a variable is created the moment a value is first assigned to it. [S1]
- **Dynamically typed** — variables aren't bound to a type and can change type after being set. [S1]
- **Casting** — `str()`, `int()`, `float()` explicitly specify a variable's data type. [S1]
- **`type()` function** — returns a variable's current data type. [S1]
- **Quote flexibility** — string variables can use single or double quotes interchangeably. [S1]
- **Case sensitivity** — variable names are case-sensitive (`a` and `A` are different variables). [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Type can change mid-program** — `x = 4` (int) then `x = "Sally"` (str) is legal; the variable simply now refers to a different type of object. [S1]

## 📖 세부 내용 (Details)
- Basic creation: `x = 5; y = "John"`. [S1]
- Type change: `x = 4  # int` then `x = "Sally"  # str`. [S1]
- Casting: `x = str(3); y = int(3); z = float(3)`. [S1]
- Get type: `print(type(x))`. [S1]
- Case sensitivity: `a = 4; A = "Sally"` creates two distinct variables. [S1]

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

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — Data Types/Casting 챕터에서 이 개념이 더 깊이 다뤄진다. [S1]

## 💻 코드 패턴 (Code patterns)
Dynamic typing and casting (Python):
```python
x = 4       # x is of type int
x = "Sally" # x is now of type str

x = str(3)    # x will be '3'
y = int(3)    # y will be 3
z = float(3)  # z will be 3.0
```

## ✅ 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 Variable Names]], [[Python Data Types]], [[Python Casting]], [[Python Global Variables]]
- **참조 맥락:** Python 변수 개념의 진입점 — 동적 타이핑과 캐스팅으로 이어진다.

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

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