Is there an Object spread syntax in python 2.7x like in Javascript?

Armeen Harwood picture Armeen Harwood · Dec 18, 2017 · Viewed 13k times · Source

How can I spread an objects/dict(?) properties and into a new object/dict?

Simple Javascript:

const obj = {x: '2', y: '1'}
const thing = {...obj, x: '1'}
// thing = {x: '1', y: 1}

Python:

regions = []
for doc in locations_addresses['documents']:
   regions.append(
        {
            **doc, # this will not work
            'lat': '1234',
            'lng': '1234',

        }
    )
return json.dumps({'regions': regions, 'offices': []})

Answer

juanpa.arrivillaga picture juanpa.arrivillaga · Dec 18, 2017

If you had Python >=3.5, you can use key-word expansion in dict literal:

>>> d = {'x': '2', 'y': '1'}
>>> {**d, 'x':1}
{'x': 1, 'y': '1'}

This is sometimes referred to as "splatting".

If you are on Python 2.7, well, there is no equivalent. That's the problem with using something that is over 7 years old. You'll have to do something like:

>>> d = {'x': '2', 'y': '1'}
>>> x = {'x':1}
>>> x.update(d)
>>> x
{'x': '2', 'y': '1'}