CODEWITHSUNDEEP
pythondictionarykeyword-argument
teaforthecat
teaforthecat

Reputation: 5083

Converting Python dict to kwargs?

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')?

See also: What do ** (double star/asterisk) and * (star/asterisk) mean in a function call? - the corresponding question for people who encounter the syntax and are confused by it.

Upvotes: 482

Views: 273753

Answers (3)

Ben Mares
Ben Mares

Reputation: 2157

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

Upvotes: 19

Vishvajit Pathak
Vishvajit Pathak

Reputation: 3711

** 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')

Upvotes: 52

unutbu
unutbu

Reputation: 879291

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

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

is equivalent to

func(type='Event')

Upvotes: 851

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