How to Create a Data Helper Class in Python for JSON Files

import json
from pathlib import Path


class DataHelper:
    """Simple beginner-friendly helper for reading and writing JSON data files."""

    @staticmethod
    def read_json(filename):
        file_path = Path(filename)
        if file_path.exists():
            with file_path.open("r", encoding="utf-8") as f:
                return json.load(f)
        return []

    @staticmethod
    def write_json(filename, data):
        file_path = Path(filename)
        with file_path.open("w", encoding="utf-8") as f:
            json.dump(data, f, indent=4)
        return f"Saved {len(data)} records to {filename}"

    @staticmethod
    def filter_records(data, key, value):
        return [record for record in data if record.get(key) == value]

    @staticmethod
    def summarize(data, key):
        summary = {}
        for record in data:
            field_value = record.get(key, "unknown")
            summary[field_value] = summary.get(field_value, 0) + 1
        return summary


if __name__ == "__main__":
    # Create example data
    sample_data = [
        {"id": 1, "category": "books", "price": 10},
        {"id": 2, "category": "music", "price": 12},
        {"id": 3, "category": "books", "price": 9},
    ]

    # Save and reload data
    print(DataHelper.write_json("data.json", sample_data))
    loaded = DataHelper.read_json("data.json")

    # Demonstrate filtering
    books = DataHelper.filter_records(loaded, "category", "books")
    print("Filtered books:", books)

    # Demonstrate summarization
    summary = DataHelper.summarize(loaded, "category")
    print("Category summary:", summary)