---
id: php-json
title: "PHP JSON"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["json_encode", "json_decode", "PHP JSON"]
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", "json"]
raw_sources: ["https://www.w3schools.com/php/php_json.asp"]
applied_in: []
github_commit: ""
---

# [[PHP JSON]]

## 🎯 한 줄 통찰 (One-line insight)
`json_decode()` returns a PHP OBJECT by default — accessed via `->property` syntax — but passing `true` as the second argument switches it to an ASSOCIATIVE ARRAY instead, accessed via `["key"]` syntax, meaning the exact same JSON string can be decoded into two structurally different PHP representations depending on one boolean flag. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`json_encode($value)`** — converts a PHP value (array/object) to a JSON string. [S1]
- **`json_decode($jsonString)`** — converts JSON into a PHP object by default. [S1]
- **`json_decode($jsonString, true)`** — the second `true` argument decodes into an associative array instead. [S1]
- **Associative array → JSON object** — `array("Peter"=>35, ...)` encodes to a JSON object `{"Peter":35,...}`. [S1]
- **Indexed array → JSON array** — `array("Volvo", "BMW", "Toyota")` encodes to a JSON array `["Volvo","BMW","Toyota"]`. [S1]

## 📖 세부 내용 (Details)
- Encode associative array (→ JSON object): `$age = array("Peter"=>35, "Ben"=>37, "Joe"=>43); echo json_encode($age);`. [S1]
- Encode indexed array (→ JSON array): `$cars = array("Volvo", "BMW", "Toyota"); echo json_encode($cars);`. [S1]
- Decode to object (default): `$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}'; $obj = json_decode($jsonobj); echo $obj->Peter;`. [S1]
- Decode to associative array (with `true`): `$arr = json_decode($jsonobj, true); echo $arr["Peter"];`. [S1]
- Loop through decoded object: `foreach($obj as $key => $value) { echo $key . " => " . $value . "<br>"; }`. [S1]
- Loop through decoded associative array: same `foreach ($arr as $key => $value)` pattern works identically. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **디코딩 결과 타입의 이중성**: json_decode()는 기본적으로 객체를 반환하지만, 두 번째 인자로 true를 주면 연관 배열로 반환된다는 점이 핵심 차이로 강조됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 나이 데이터를 JSON으로 인코딩/디코딩하고 foreach로 순회하는 것이 API 데이터 교환의 표준 패턴이다. [S1]

## 💻 코드 패턴 (Code patterns)
Decoding JSON to an associative array vs. object (PHP):
```php
$jsonobj = '{"Peter":35,"Ben":37,"Joe":43}';
$obj = json_decode($jsonobj);          // object: $obj->Peter
$arr = json_decode($jsonobj, true);    // associative array: $arr["Peter"]
```

## ✅ 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 Callback Functions]], [[PHP Arrays Associative]], [[PHP Exceptions]]
- **참조 맥락:** JSON 인코딩/디코딩 — 예외 처리(Exceptions & Errors) 섹션으로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP and JSON — https://www.w3schools.com/php/php_json.asp

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