function getParams(data) { return { id: data && data.uuid } } So the above represents a common pattern in Javascript for accessing the items of an object.
What is the most commonly used equivalent practice in Python for accessing items of a dict?
Would it be like so?
def getParams(data): params = {} if data is not None and hasattr(data, "id"): params["id"] = data["id"] return params If not, what is the best practice? Thanks.
If you want to get a key from a dict without knowing if it's there, you can use the get method of dicts. It returns None (or a specific default value) if the key isn't there:
>>> x = {} >>> print(x.get('a')) None >>> print(x.get('a', 'default')) default 
data && data.uuid && data.uuid.someAttribute
get multiple times, like data.get('uuid', {}).get('someAttribute', None). But also look around on this site for other people asking similar questions, there are many.
get is convenient, be aware that it can be noticeably slower than more verbose code that uses in.If you mean attributes:
params['id'] = data.id if data else None If you mean items:
params['id'] = data.get('id') In both cases params['id'] will contain value or None.
Python dict is different from javascript.
def getParams(data): params = {} if data and 'id' in data.keys(): params["id"] = data["id"] return params 
'id' in data. Key checking is a key feature of dicts.'id' in data.keys() is wasteful because it has to construct the keys object. That's not so bad in Python 3 because it's a dictionary view object that accesses the underlying dict; and look-ups on dictviews are fast. But in Python 2 dict.keys() has to build a new list object, and lookups on a list involve a slow linear search rather than the fast O(1) lookup that a dictionary or set provides.You can use get method of dict. A default value can also be specified, which could be used if the specified key do not exist.
data.get('id', None) 
data.foo) or items (data['foo'])? JavaScript uses the same syntax for these, but they are distinct in Python.datais a python dictionary.