Python dict.get('key') versus dict['key'] [duplicate]
This is simply how the get() method is defined.
From the Python docs:
Return the value for key if key is in the dictionary, else default. If default is not given, it defaults to None, so that this method never raises a KeyError.
The default "not-found" return value is None. You can return any other default value.
d = dict()d.get('xyz', 42) # returns 42
Accessing by brackets does not have a default but the get method does and the default is None. From the docs for get (via a = dict(); help(a.get))
Help on built-in function get:get(...) D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None.
Simply because [ 1 ] the key is not in the map and [ 2 ] those two operations are different in nature.
From dict Mapping Types:
d[key]Return the item of d with key key. Raises a KeyError if key is not in the map.
get(key[, default])Return the value for key if key is in the dictionary, else default. If default is not given, it defaults to None, so that this method never raises a KeyError.