Build a Progress Callback Function for Loops in Python

def run_with_progress(items, desc="Processing", step_callback=None):
    """Run a loop with progress updates via callback."""
    total = len(items)
    for idx, item in enumerate(items):
        # Process the item (simulated work here)
        result = item * 2

        # Build progress data dictionary
        if step_callback:
            progress_data = {
                "index": idx + 1,
                "total": total,
                "percent": round((idx + 1) / total * 100, 1),
                "item": item,
                "result": result,
            }
            step_callback(progress_data)

    return total


def print_progress(data):
    """Example step callback that logs progress to console."""
    suffix = f"({data['index']}/{data['total']})"
    print(
        f"{data['percent']}% {suffix}: "
        f"item={data['item']} -> result={data['result']}"
    )


if __name__ == "__main__":
    items = [10, 20, 30, 40, 50]
    completed = run_with_progress(items, step_callback=print_progress)
    print(f"\nCompleted {completed} items.")