2nd/10_Wiki/Dev/Topic_PHP/PHP_Arrays_Remove.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
php-arrays-remove	PHP Arrays Remove	Programming_Language	draft	conceptual		unset array_splice PHP 배열 삭제		B	0.9	2026-07-04	2026-07-04			php programming w3schools arrays remove unset	https://www.w3schools.com/php/php_arrays_remove.asp

PHP Arrays Remove

🎯 한 줄 통찰 (One-line insight)

array_splice() and unset() handle re-indexing completely differently — array_splice() automatically re-indexes the array from 0 after removal, while unset() leaves a GAP in the index sequence (removing index 1 leaves indices 0, 2, 3... with no 1), a distinction that matters if code later assumes contiguous indices. [S1]

🧠 핵심 개념 (Core concepts)

• array_splice($arr, start, length) — removes a portion and auto-re-indexes from 0. [S1]
• unset($arr[key]) — removes one item by key/index; does NOT re-index, leaving gaps. [S1]
• unset() accepts multiple arguments — can remove several items in one call. [S1]
• array_diff($arr, [values]) — returns a NEW array excluding specified VALUES (not keys). [S1]
• array_pop($arr) — removes the last item. [S1]
• array_shift($arr) — removes the first item. [S1]

📖 세부 내용 (Details)

• array_splice (re-indexes): $cars = array("Volvo", "BMW", "Toyota"); array_splice($cars, 1, 1); // removes "BMW", re-indexed to [0=>"Volvo", 1=>"Toyota"]. [S1]
• unset (leaves a gap): $cars = array("Volvo", "BMW", "Toyota"); unset($cars[1]); // [0=>"Volvo", 2=>"Toyota"] — no index 1. [S1]
• unset multiple: unset($cars[0], $cars[1]);. [S1]
• unset by key (associative): unset($cars["model"]);. [S1]
• array_diff (value-based removal): $newarray = array_diff($cars, ["Mustang", 1964]); // note: values, not keys. [S1]
• array_pop / array_shift: array_pop($cars); // removes last; array_shift($cars); // removes first. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 재인덱싱 여부의 차이: array_splice()는 삭제 후 0부터 자동 재인덱싱하지만, unset()은 재인덱싱하지 않아 인덱스에 공백이 생긴다는 점이 명확히 대비됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — array_diff()로 특정 값들을 제외한 새 배열을 만드는 패턴이 연관 배열 필터링의 대표 사례다. [S1]

💻 코드 패턴 (Code patterns)

unset() leaves an index gap, unlike array_splice() (PHP):

$cars = array("Volvo", "BMW", "Toyota");
unset($cars[1]);
var_dump($cars); // [0]=>"Volvo", [2]=>"Toyota" — index 1 is missing, not re-indexed

✅ 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: PHP Tutorial
• 관련 개념: PHP Arrays Add, PHP Arrays Sort, PHP Arrays Functions
• 참조 맥락: 배열 항목 삭제 — 정렬(Sort) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — PHP Delete Array Items — https://www.w3schools.com/php/php_arrays_remove.asp

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "PHP Delete Array Items" page (Astra wiki-curation, P-Reinforce v3.1 format).