JSON - Encoding a List of Serializable Objects

Question

I have a the following code. In essence, there are two classes - Lego Themes which acts as a container for Lego Theme objects. I have implemented a method "saveThemes()" that basically iterates through the themes - converts the individually stored Lego Objects into JSON and then adds them to a variable (resultantJson).

However, I appreciate this is a bit of a 'hack'. Should I be able to do a json.dumps() of the self__.themes directly (it currently says the object is serializable)?

import json


class LegoThemes:
    def __init__(self):
        self.__themes = []

    def saveThemes(self):
        resultantJson = ""

        for theme in self.__themes:
            resultantJson += json.dumps(theme.__dict__)

        # TODO: Output resultantJSON to .JSON file.
        return resultantJson

    # TODO: implement loadThemes(self)

    def addTheme(self, theme):
        self.__themes.append(theme)


class LegoTheme:
    def __init__(self, title, description, thumbnailImage, logoImage, url):
        self.__title = title
        self.__description = description
        self.__thumbnailImage = thumbnailImage
        self.__logoImage = logoImage
        self.__url = url

    def getTitle(self):
        return self.__title


testThemeOne = LegoTheme(
    "Test Theme One Title",
    "Test Theme One Description.",
    "Test Theme One Thumbnail Image",
    "Test Theme One Logo Image",
    "Test Theme One URL",
)

testThemeTwo = LegoTheme(
    "Test Theme Two Title",
    "Test Theme Two Description.",
    "Test Theme Two Thumbnail Image",
    "Test Theme Two Logo Image",
    "Test Theme Two URL",
)

testThemeThree = LegoTheme(
    "Test Theme Three Title",
    "Test Theme Three Description.",
    "Test Theme Three Thumbnail Image",
    "Test Theme Three Logo Image",
    "Test Theme Three URL",
)

legoThemes = LegoThemes()

legoThemes.addTheme(testThemeOne)
legoThemes.addTheme(testThemeTwo)
legoThemes.addTheme(testThemeThree)

print(legoThemes.saveThemes())

btw the string returned from saveThemes() is technically not json. — quamrana
– quamrana, Commented Nov 5, 2020 at 14:07
@quamrana Because they are not encapsulated within one JSON 'string'? — JHarley1
– JHarley1, Commented Nov 5, 2020 at 14:16
If you look on the website the only allowed top level objects are list [] or object {}. You have to ask yourself what would you expect a json decode of the result of saveThemes() to produce? — quamrana
– quamrana, Commented Nov 5, 2020 at 14:28

quamrana · Accepted Answer · 2020-11-05 14:10:16Z

1

You can convert a list of the __dict__ member as json:

    def saveJson(self):
        return json.dumps([t.__dict__ for t in self.__themes])

answered Nov 5, 2020 at 14:10

quamrana

39.5k13 gold badges57 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

JSON - Encoding a List of Serializable Objects

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related