Python创建并保存json文件，支持数据更新保存

import json

class Params():
    """Class that loads hyperparameters from a json file.
        Example:
        ```
        params = Params(json_path)
        print(params.learning_rate)
        params.learning_rate = 0.5  # change the value of learning_rate in params
        ```
        """
    def __init__(self, json_path):
        with open(json_path) as f:
            params = json.load(f)  # 将json格式数据转换为字典
            self.__dict__.update(params)

    def save(self, json_path):
        with open(json_path, 'w') as f:
            json.dump(self.__dict__, f, indent=4)  # indent缩进级别进行漂亮打印

    def update(self, json_path):
        """Loads parameters from json file"""
        with open(json_path) as f:
            params = json.load(f)
            self.__dict__.update(params)

    @property  # Python内置的@property装饰器就是负责把一个方法变成属性调用的
    def dict(self):
        """Gives dict-like access to Params instance by `params.dict['learning_rate']"""
        return self.__dict__


if __name__ == '__main__':
    parameters = {"SEED": 1,
                  "dataset": "Omniglot",
                  "meta_lr": 1e-3,
                  "num_episodes": 5000,
                  "num_classes": 5,
                  "num_samples": 1,
                  "num_query": 10,
                  "num_steps": 100,
                  "num_inner_tasks": 8,
                  "num_train_updates": 1,
                  "num_eval_updates": 1,
                  "save_summary_steps": 100,
                  "num_workers": 1
                  }
    json_str = json.dumps(parameters, indent=4)

    with open('params.json', 'w') as f:  # 创建一个params.json文件
        f.write(json_str)  # 将json_str写到文件中

    params = Params('params.json')
    params.SEED = 2   # 修改json中的数据
    params.save('params.json')  # 将修改后的数据保存