---
id: php-arrays-remove
title: "PHP Arrays Remove"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["unset", "array_splice", "PHP 배열 삭제"]
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: ["php", "programming", "w3schools", "arrays", "remove", "unset"]
raw_sources: ["https://www.w3schools.com/php/php_arrays_remove.asp"]
applied_in: []
github_commit: ""
---

# [[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):
```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).