Converting Python dict to kwargs?

Question

I want to build a query for sunburnt(solr interface) using class inheritance and therefore adding key - value pairs together. The sunburnt interface takes keyword arguments. How can I transform a dict ({'type':'Event'}) into keyword arguments (type='Event')?

Solution 1

Use the double-star (aka double-splat?) operator:

func(**{'type':'Event'})

is equivalent to

func(type='Event')

Solution 2

** operator would be helpful here.

** operator will unpack the dict elements and thus **{'type':'Event'} would be treated as type='Event'

func(**{'type':'Event'}) is same as func(type='Event') i.e the dict elements would be converted to the keyword arguments.

FYI

* will unpack the list elements and they would be treated as positional arguments.

func(*['one', 'two']) is same as func('one', 'two')

Solution 3

Here is a complete example showing how to use the ** operator to pass values from a dictionary as keyword arguments.

>>> def f(x=2):
...     print(x)
... 
>>> new_x = {'x': 4}
>>> f()        #    default value x=2
2
>>> f(x=3)     #   explicit value x=3
3
>>> f(**new_x) # dictionary value x=4 
4

Comments

[James Khoury]

and if you already have a dict object called "myDict" you just func(**myDict) .i.e myDict = {"type": "event"}

[dreftymac]

This is pretty well-covered in the python standard documentation. See also: stackoverflow.com/questions/1137161. (dmid://juice_cobra_hush)

[timmins]

This is brilliantly helpful, especially when using converting dictionaries into Swagger model instances. Thanks.