db.py

import os
from turtle import fd
import pandas as pd
import numpy as np


class Database:
    FILENAME = 'db.csv'

    def __init__(self, filename=FILENAME) -> None:
        if not os.path.exists(filename):
            with open(filename, 'w') as f:
                f.write('index,lon,lat,tag')

        self.load()

    def __iter__(self):
        for row in self.db.itertuples():
            yield tuple(row)

    def load(self, filename=FILENAME):
        if not os.path.exists(filename):
            raise FileNotFoundError(f"db file {filename} not found")
        self.db = pd.read_csv(filename, dtype={
            'lat': np.float64, 'lon': np.float64, 'tag': np.string_})

    def save(self, filename=FILENAME):
        self.db.to_csv(filename, index=False)

    def insert(self, lat, lon, tag=np.nan):
        self.db.loc[len(self.db), self.db.columns] = lat, lon, tag
        self.save()