---
id: php-looping-for
title: "PHP Looping For"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["for loop", "PHP for 반복문"]
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", "loops", "for"]
raw_sources: ["https://www.w3schools.com/php/php_looping_for.asp"]
applied_in: []
github_commit: ""
---

# [[PHP Looping For]]

## 🎯 한 줄 통찰 (One-line insight)
The `for` loop's three clauses each run at a different time relative to the loop body — initialization runs ONCE before anything, the condition runs BEFORE each iteration, and the increment runs AFTER each iteration — meaning changing the increment direction (`$x++` to `$x--`) alone, combined with a matching condition, is all that's needed to count backwards instead of forwards. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`for (init; condition; increment) { ... }`** — init runs once; condition checked before each iteration; increment runs after each iteration. [S1]
- **Use case** — when the number of iterations is known ahead of time. [S1]
- **Counting down** — reversing the increment (`$x--`) and flipping the condition (`$x >= 0`). [S1]
- **`break`** / **`continue`** — work the same as other loop types. [S1]
- **Custom step size** — `$x += 10` for stepping by 10 instead of 1. [S1]

## 📖 세부 내용 (Details)
- Counting up: `for ($x = 0; $x <= 10; $x++) { echo "The number is: $x <br>"; }`. [S1]
- Counting down: `for ($x = 10; $x >= 0; $x--) { echo "The number is: $x <br>"; }`. [S1]
- Break: `for ($x = 0; $x <= 10; $x++) { if ($x == 3) break; echo "The number is: $x <br>"; }`. [S1]
- Continue: `for ($x = 0; $x <= 10; $x++) { if ($x == 3) continue; echo "The number is: $x <br>"; }`. [S1]
- Step 10: `for ($x = 0; $x <= 100; $x += 10) { echo "The number is: $x <br>"; }`. [S1]

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

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 10부터 0까지 카운트다운하는 예제가 증감 방향 조정의 대표 패턴이다. [S1]

## 💻 코드 패턴 (Code patterns)
Counting down with a for loop (PHP):
```php
for ($x = 10; $x >= 0; $x--) {
    echo "The number is: $x <br>";
}
```

## ✅ 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 Looping Do While]], [[PHP Looping Foreach]], [[PHP Looping Break]]
- **참조 맥락:** 반복 횟수를 아는 경우의 표준 반복문 — foreach 루프 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP for Loop — https://www.w3schools.com/php/php_looping_for.asp

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