2nd/10_Wiki/Dev/Topic_Python/Python_For_Loops.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
python-for-loops	Python For Loops	Programming_Language	draft	conceptual		for loop range() nested loops 파이썬 for 반복문		B	0.9	2026-07-04	2026-07-04			python programming w3schools for loop range	https://www.w3schools.com/python/python_for_loops.asp

Python For Loops

🎯 한 줄 통찰 (One-line insight)

Python's for loop is an iterator over any sequence (list, tuple, dict, set, string) rather than a counter-based loop like in C-style languages, and range(6) yields 0 through 5, not 0 through 6 — the end value is always exclusive. [S1]

🧠 핵심 개념 (Core concepts)

• for loop — iterates over a sequence (list, tuple, dictionary, set, string); no indexing variable needed. [S1]
• Iterates any sequence, including strings — for x in "banana": loops over characters. [S1]
• break — exits the loop early. [S1]
• continue — skips to the next iteration. [S1]
• range() — generates a number sequence; default starts at 0, increments by 1, end value EXCLUSIVE (range(6) = 0..5). [S1]
• range(start, stop) — custom start. [S1]
• range(start, stop, step) — custom increment. [S1]
• else — runs when the loop finishes normally; skipped if stopped by break (same rule as while loops). [S1]
• Nested loops — inner loop runs fully for each iteration of the outer loop. [S1]
• pass — required placeholder for an otherwise-empty for loop body. [S1]

🧩 추출된 패턴 (Extracted patterns)

• break-before-vs-after-print changes output — placing the if x == "banana": break check BEFORE the print vs. AFTER it changes whether "banana" itself gets printed before the loop exits — order within the loop body matters. [S1]

📖 세부 내용 (Details)

• Basic loop: fruits = ["apple","banana","cherry"]; for x in fruits: print(x). [S1]
• range() exclusive end: for x in range(6): print(x) → prints 0,1,2,3,4,5. [S1]
• range() with start: for x in range(2, 6): → 2,3,4,5. [S1]
• range() with step: for x in range(2, 30, 3):. [S1]
• Nested loop: for x in adj: for y in fruits: print(x, y). [S1]
• else on natural completion: for x in range(6): print(x) else: print("Finally finished!"). [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 이후 List Comprehension 챕터에서 이 for 순회가 한 줄 표현식으로 압축된다. [S1]

💻 코드 패턴 (Code patterns)

range() with custom start/stop/step (Python):

for x in range(2, 30, 3):
    print(x)

Nested loop over two lists (Python):

adj = ["red", "big", "tasty"]
fruits = ["apple", "banana", "cherry"]
for x in adj:
    for y in fruits:
        print(x, y)

✅ 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 While Loops, Python Lists Comprehension, Python Range
• 참조 맥락: Python 2대 반복문 중 하나 — List Comprehension으로 압축 가능한 순회 패턴.

📚 출처 (Sources)

• [S1] W3Schools — Python For Loops — https://www.w3schools.com/python/python_for_loops.asp

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "Python For Loops" page (Astra wiki-curation, P-Reinforce v3.1 format).