How to use a dot "." to access members of dictionary?
I've always kept this around in a util file. You can use it as a mixin on your own classes too.
class dotdict(dict): """dot.notation access to dictionary attributes""" __getattr__ = dict.get __setattr__ = dict.__setitem__ __delattr__ = dict.__delitem__mydict = {'val':'it works'}nested_dict = {'val':'nested works too'}mydict = dotdict(mydict)mydict.val# 'it works'mydict.nested = dotdict(nested_dict)mydict.nested.val# 'nested works too'
You can do it using this class I just made. With this class you can use the Map
object like another dictionary(including json serialization) or with the dot notation. I hope to help you:
class Map(dict): """ Example: m = Map({'first_name': 'Eduardo'}, last_name='Pool', age=24, sports=['Soccer']) """ def __init__(self, *args, **kwargs): super(Map, self).__init__(*args, **kwargs) for arg in args: if isinstance(arg, dict): for k, v in arg.iteritems(): self[k] = v if kwargs: for k, v in kwargs.iteritems(): self[k] = v def __getattr__(self, attr): return self.get(attr) def __setattr__(self, key, value): self.__setitem__(key, value) def __setitem__(self, key, value): super(Map, self).__setitem__(key, value) self.__dict__.update({key: value}) def __delattr__(self, item): self.__delitem__(item) def __delitem__(self, key): super(Map, self).__delitem__(key) del self.__dict__[key]
Usage examples:
m = Map({'first_name': 'Eduardo'}, last_name='Pool', age=24, sports=['Soccer'])# Add new keym.new_key = 'Hello world!'# Orm['new_key'] = 'Hello world!'print m.new_keyprint m['new_key']# Update valuesm.new_key = 'Yay!'# Orm['new_key'] = 'Yay!'# Delete keydel m.new_key# Ordel m['new_key']
Install dotmap
via pip
pip install dotmap
It does everything you want it to do and subclasses dict
, so it operates like a normal dictionary:
from dotmap import DotMapm = DotMap()m.hello = 'world'm.hellom.hello += '!'# m.hello and m['hello'] now both return 'world!'m.val = 5m.val2 = 'Sam'
On top of that, you can convert it to and from dict
objects:
d = m.toDict()m = DotMap(d) # automatic conversion in constructor
This means that if something you want to access is already in dict
form, you can turn it into a DotMap
for easy access:
import jsonjsonDict = json.loads(text)data = DotMap(jsonDict)print data.location.city
Finally, it automatically creates new child DotMap
instances so you can do things like this:
m = DotMap()m.people.steve.age = 31
Comparison to Bunch
Full disclosure: I am the creator of the DotMap. I created it because Bunch
was missing these features
- remembering the order items are added and iterating in that order
- automatic child
DotMap
creation, which saves time and makes for cleaner code when you have a lot of hierarchy - constructing from a
dict
and recursively converting all childdict
instances toDotMap