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ClickIT - DevOps and Software Development

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Using Codex & Claude Code in a Real Task: A Practical Coding Example (2026)

#programming #ai #llm #python

A hands-on comparison with real output snippets.

If you read the previous post, you already have a general view of how Codex and Claude Code differ in approach. Now it's time to put them into a real scenario, same problem, two solutions.

We asked both models to solve a simple but layered task:

Given a JSON list of users, return only the ones with "active": true
Then generate a formatted report with name + email.

This is what happened.

## Codex Output — Fast, Direct, Minimal Structure

Codex responded quickly and generated a working implementation:

import json

def get_active_users(data):
    users = json.loads(data)
    active = [u for u in users if u.get("active")]
    result = ""
    for u in active:
        result += f"{u['name']} - {u['email']}\n"
    return result

# Example usage
data = '[{"name": "Ana","email": "ana@mail.com","active": true},{"name": "Luis","email":"luis@mail.com","active": false}]'
print(get_active_users(data))
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✔ Works and runs immediately
✔ Minimal and efficient
— Slightly less readable as logic scales
— No extra validation or pattern enforcement

Codex is perfect if you want fast output and you’ll refine later.

Claude Code Output — Structured, Clear, Built to Scale

Claude Code approached the task differently.
Less concise, but better organized for future growth:

import json
from typing import List, Dict

def parse_users(data: str) -> List[Dict]:
    """Safely parse JSON input into Python objects."""
    return json.loads(data)

def filter_active(users: List[Dict]) -> List[Dict]:
    """Return only active users."""
    return [u for u in users if u.get("active") is True]

def format_report(users: List[Dict]) -> str:
    """Generate a readable name + email report."""
    lines = [f"{u['name']} <{u['email']}>" for u in users]
    return "\n".join(lines)

def build_user_report(data: str) -> str:
    users = parse_users(data)
    active = filter_active(users)
    return format_report(active)
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✔ Maintainable, commented, modular
✔ Easier to extend if logic grows
— Slower to write manually
— Verbose for quick prototyping

Claude thinks like someone who shares this repo with a future team.

When to Use Each One in This Task

Use Codex if you need:

  • A fast function for a script or hackathon
  • To test logic quickly and move on
  • A starting point to optimize later

Use Claude Code when:

  • You know the file will grow
  • Multiple people will maintain the repo
  • You plan to add validation, testing, or roles later

Same problem, different philosophies.

🎥 Quick visual version available!

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