CODEWITHSUNDEEP
pythonclassobject
hegdep
hegdep

Reputation: 596

Override class variables within a loop

Assuming I have a class which is defined with variables as follows:

import numpy as np
class DataShell:
    dS=''
    name=''
    type=''
    some other variables

I initialize an object 

Obj=DataShell()

I have a dictionary L and I want to assign the values from the dictionary to the class variables of the object

{'name': 'abc', 'type': 'def', 'dS': 'hij'}

I am trying out the following code to do this:

attributes = [attr for attr in dir(Obj) 
              if not attr.startswith('__')]
for key in L:
    for el in attributes:
        if key==el:
            Obj.el=str(L[key])

This is creating a new variable in my object called 'el' and assigning a value to it instead of changing my Obj.name, Obj.dS or Obj.type

Upvotes: 0

Views: 472

Answers (3)

Jab
Jab

Reputation: 27485

Why not make an initialization function that takes the values?

class DataShell:
    def __init__(self, dS='', name='', type=''):
        dS = dS
        name = name
        type = type

Then use:

DataShell(**L)

Or even easier in Python 3 use dataclass

import dataclass 

@dataclass
class DataShell:
    dS: str  = ''
    name: str  = ''
    type: str  = ''

Obj = DataShell(**L)

Upvotes: 4

Anurag
Anurag

Reputation: 3114

The code you copied in the question is not at all working. I tried to modify your code and now it is working -

class DataShell:
    dS=''
    name=''
    type=''

Obj=DataShell()
print(id(Obj))
L = {'name': 'abc', 'type': 'def', 'dS': 'hij'}
attributes = [attr for attr in dir(Obj) 
              if not attr.startswith('__')]
print(attributes)
for key in L:
    for el in attributes:
        if key==el:
            if hasattr(Obj, el):
                setattr(Obj, el, L[key]) 

print(id(Obj))
print(dir(Obj))
print(Obj.dS)
print(Obj.name)
print(Obj.type)

use setattr for dynamically setting the class attributes

Upvotes: 1

kingkupps
kingkupps

Reputation: 3494

You can use setattr and hasattr. For example:

class MyClass(object):
    attr1 = 1
    attr2 = 2

myobject = MyClass()

m = {'attr1': 19, 'some_other_name': 'blah'}
for name, value in m.items():
    if hasattr(myobject, name):
        setattr(myobject, name, value)

print(myobject.attr1)  # 19

Upvotes: 4

Related Questions