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Python 将字典转换为 JSON

news 2025/6/22 14:47:45

在 Python 中，可以使用 json 模块将字典转换为 JSON 格式的字符串。该模块提供了 json.dumps() 方法，用于将 Python 对象（如字典、列表）序列化为 JSON 字符串。

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1、问题背景

用户想要将一个 Python 字典转换为 JSON 格式，但是遇到了一个错误，错误信息提示对象 City 和 Route 不可序列化。

以下是他尝试的代码：

class City:"""Stores city info"""def __init__(self, code, name, country, continent, timezone, coordinates, population, region):self.code = codeself.name = nameself.country = countryself.continent = continentself.timezone = timezoneself.coordinates = coordinatesself.population = populationself.region = regiondef to_json(self):return {'code': self.code, 'name': self.name, 'country': self.country, 'continent': self.continent, 'timezone':  self.timezone, 'coordinates': self.coordinates, 'population': self.population, 'region': self.region}class Route:"""Stores route info"""def __init__(self, src, dest, dist):self.flight_path = src + '-' + destself.src = srcself.dest = destself.dist = distdef to_json(self):return {'source': self.src, 'destination': self.dest, 'distance': self.dist}def map_to_json(my_file, air_map):"""Saves JSON Data"""with open(my_file, 'w') as outfile:for entry in air_map.cities:json.dumps(air_map.cities[entry].to_json(), outfile)for entry in air_map.routes:json.dumps(air_map.routes[entry].to_json(), outfile)outfile.close()

2、解决方案

为了解决问题，用户需要使用 to_json() 方法将每个对象转换为一个字典，然后再使用 json.dumps() 方法将字典转换为 JSON 格式。
以下是修改后的代码：

class City:"""Stores city info"""def __init__(self, code, name, country, continent, timezone, coordinates, population, region):self.code = codeself.name = nameself.country = countryself.continent = continentself.timezone = timezoneself.coordinates = coordinatesself.population = populationself.region = regiondef to_json(self):return {'code': self.code, 'name': self.name, 'country': self.country, 'continent': self.continent, 'timezone':  self.timezone, 'coordinates': self.coordinates, 'population': self.population, 'region': self.region}class Route:"""Stores route info"""def __init__(self, src, dest, dist):self.flight_path = src + '-' + destself.src = srcself.dest = destself.dist = distdef to_json(self):return {'source': self.src, 'destination': self.dest, 'distance': self.dist}def map_to_json(my_file, air_map):"""Saves JSON Data"""with open(my_file, 'w') as outfile:for entry in air_map.cities:json.dumps(air_map.cities[entry].to_json(), outfile)for entry in air_map.routes:json.dumps(air_map.routes[entry].to_json(), outfile)outfile.close()air_map = Map()
city1 = City('ABC', 'City1', 'Country1', 'Continent1', 'Timezone1', 'Coordinates1', 100000, 'Region1')
city2 = City('DEF', 'City2', 'Country2', 'Continent2', 'Timezone2', 'Coordinates2', 200000, 'Region2')
city3 = City('GHI', 'City3', 'Country3', 'Continent3', 'Timezone3', 'Coordinates3', 300000, 'Region3')
route1 = Route('ABC','DEF', 100)
route2 = Route('DEF','GHI', 200)
air_map.cities['ABC'] = city1
air_map.cities['DEF'] = city2
air_map.cities['GHI'] = city3
air_map.routes['ABC-DEF'] = route1
air_map.routes['DEF-GHI'] = route2map_to_json('map.json', air_map)