Set attributes from dictionary in python


Is it possible to create an object from a dictionary in python in such a way that each key is an attribute of that object?

Something like this:

 d = { 'name': 'Oscar', 'lastName': 'Reyes', 'age':32 }

 e = Employee(d) 
 print # Oscar 
 print e.age + 10 # 42 

I think it would be pretty much the inverse of this question: Python dictionary from an object’s fields

Asked By: OscarRyz



Sure, something like this:

class Employee(object):
    def __init__(self, initial_data):
        for key in initial_data:
            setattr(self, key, initial_data[key])


As Brent Nash suggests, you can make this more flexible by allowing keyword arguments as well:

class Employee(object):
    def __init__(self, *initial_data, **kwargs):
        for dictionary in initial_data:
            for key in dictionary:
                setattr(self, key, dictionary[key])
        for key in kwargs:
            setattr(self, key, kwargs[key])

Then you can call it like this:

e = Employee({"name": "abc", "age": 32})

or like this:

e = Employee(name="abc", age=32)

or even like this:

employee_template = {"role": "minion"}
e = Employee(employee_template, name="abc", age=32)
Answered By: Ian Clelland

You can access the attributes of an object with __dict__, and call the update method on it:

>>> class Employee(object):
...     def __init__(self, _dict):
...         self.__dict__.update(_dict)

>>> dict = { 'name': 'Oscar', 'lastName': 'Reyes', 'age':32 }

>>> e = Employee(dict)


>>> e.age
Answered By: Dave Kirby

I think that answer using settattr are the way to go if you really need to support dict.

But if Employee object is just a structure which you can access with dot syntax (.name) instead of dict syntax (['name']), you can use namedtuple like this:

from collections import namedtuple

Employee = namedtuple('Employee', 'name age')
e = Employee('noname01', 6)
print e
#>> Employee(name='noname01', age=6)

# create Employee from dictionary
d = {'name': 'noname02', 'age': 7}
e = Employee(**d)
print e
#>> Employee(name='noname02', age=7)
print e._asdict()
#>> {'age': 7, 'name': 'noname02'}

You do have _asdict() method to access all properties as dictionary, but you cannot add additional attributes later, only during the construction.

Answered By: van

Setting attributes in this way is almost certainly not the best way to solve a problem. Either:

  1. You know what all the fields should be ahead of time. In that case, you can set all the attributes explicitly. This would look like

    class Employee(object):
        def __init__(self, name, last_name, age):
   = name
            self.last_name = last_name
            self.age = age
    d = {'name': 'Oscar', 'last_name': 'Reyes', 'age':32 }
    e = Employee(**d) 
    print # Oscar 
    print e.age + 10 # 42 


  2. You don’t know what all the fields should be ahead of time. In this case, you should store the data as a dict instead of polluting an objects namespace. Attributes are for static access. This case would look like

    class Employee(object):
        def __init__(self, data):
   = data
    d = {'name': 'Oscar', 'last_name': 'Reyes', 'age':32 }
    e = Employee(d) 
    print['name'] # Oscar 
    print['age'] + 10 # 42 

Another solution that is basically equivalent to case 1 is to use a collections.namedtuple. See van’s answer for how to implement that.

Answered By: Mike Graham

Why not just use attribute names as keys to a dictionary?

class StructMyDict(dict):

     def __getattr__(self, name):
             return self[name]
         except KeyError as e:
             raise AttributeError(e)

     def __setattr__(self, name, value):
         self[name] = value

You can initialize with named arguments, a list of tuples, or a dictionary, or
individual attribute assignments, e.g.:

nautical = StructMyDict(left = "Port", right = "Starboard") # named args

nautical2 = StructMyDict({"left":"Port","right":"Starboard"}) # dictionary

nautical3 = StructMyDict([("left","Port"),("right","Starboard")]) # tuples list

nautical4 = StructMyDict()  # fields TBD
nautical4.left = "Port"
nautical4.right = "Starboard"

for x in [nautical, nautical2, nautical3, nautical4]:
    print "%s <--> %s" % (x.left,x.right)

Alternatively, instead of raising the attribute error, you can return None for unknown values. (A trick used in the web2py storage class)

Answered By: RufusVS

similar to using a dict, you could just use kwargs like so:

class Person:
   def __init__(self, **kwargs): = kwargs

   def get_property(self, key):
       return, None)

   def main():
       timmy = Person(color = 'red')
       print(timmy.get_property('color')) #prints 'red'
Answered By: Alex Spencer

say for example

class A():
    def __init__(self):

if you want to set the attributes at once

d = {'x':100,'y':300,'z':"blah"}
a = A()
Answered By: zdarkwhite

If you don’t mind using a library:

pip install domonic

then you can do:

from domonic.javascript import Object

class Employee(Object):

d = { 'name': 'Oscar', 'lastName': 'Reyes', 'age':32 }

e = Employee(d)

# {'name': 'Oscar', 'lastName': 'Reyes', 'age': 32}

Which should behave as required.

Answered By: byteface