convert python objects to string

Question

I have different python classes and I want to convert instances of these classes to ascii strings.Suppose that I have the following objects:

class A:
    name = "A"
    field = 2
    x = "a"

class B:
    name = "b"
    item = "c"

a = A()
b = B()

I want a function like serialize() which converts the objects as follows:

serialize(a) # results "A2a"
serialize(b) # results "bc"

I don't want to write a serialization function for every classe, I want to have a function capable of serializing all classes. One way is to use the dir() function to get a list of object attributes and then create a string out of them, but the dir() function does not return the attributes in the same order that they are defined. For example calling dir(a) would return ['__doc__', '__module__', 'filed', 'name', 'x'], and I cannot find out which attribute is defined first in the class.

Thanks.

You can overload the str_ or __repr magic methods however you want inside the class, or define your own class method to return the string representation however you like — G. Anderson
– G. Anderson, Commented Jan 20, 2020 at 14:43
would defining a serialize method in each of these classes be a valid option? — Ma0
– Ma0, Commented Jan 20, 2020 at 14:44
It would be best if I can do it in a general function that can serialize every class. I don't want to write a serialization function for every class! — ayyoob imani
– ayyoob imani, Commented Jan 21, 2020 at 9:39

ᴀʀᴍᴀɴ · Accepted Answer · 2020-01-20 14:47:37Z

2

You can override __repr__ function for print Object the desired way:

class A:
    name = "A"
    field = 2
    x = "a"

    def __repr__(self):
        return A.name + str(A.field) + A.x

answered Jan 20, 2020 at 14:47

ᴀʀᴍᴀɴ

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4 Comments

ayyoob imani Over a year ago

Thanks for the reply but I don't want to write a serialize function for every class. I need a general serialization function that can serialize all classes.

ᴀʀᴍᴀɴ Over a year ago

@ayyoobimani Then you need a parent class for all classes and you need to define a serializer for the parent class.

ayyoob imani Over a year ago

@ARMAN and how does the serializer know about the order that the fields are added to the class?

ᴀʀᴍᴀɴ Over a year ago

@ayyoobimani actually it doesn't, you should consider naming attributes the same way and same order in child classes in order to define the serializer general.

Renaud · Accepted Answer · 2020-01-20 15:00:09Z

1

You have to create methods in your classes: ON behalf to put the value in the class the best can be to pass argument of class A during the call%

class A:
    def __init__(self, name, field, x) :
    self.name = name
    self.field = field
    self.x = x

   def serialize(self) :
       return f"{self.name}{self.field}{self.x}"

#main:
a=A(name="a", field="field", x="x") 
result=a.serialize()
print(result)

answered Jan 20, 2020 at 15:00

Renaud

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