Why dict.get(key) instead of dict[key]?

Question

Today, I came across the dict method get which, given a key in the dictionary, returns the associated value.

For what purpose is this funct

Answer 1

It allows you to provide a default value if the key is missing:

dictionary.get("bogus", default_value)

returns default_value (whatever you choose it to be), whereas

dictionary["bogus"]

would raise a KeyError.

If omitted, default_value is None, such that

dictionary.get("bogus")  # <-- No default specified -- defaults to None

returns None just like

dictionary.get("bogus", None)

would.

Answer 2

One difference, that can be an advantage, is that if we are looking for a key that doesn't exist we will get None, not like when we use the brackets notation, in which case we will get an error thrown:

print(dictionary.get("address")) # None
print(dictionary["address"]) # throws KeyError: 'address'

Last thing that is cool about the get method, is that it receives an additional optional argument for a default value, that is if we tried to get the score value of a student, but the student doesn't have a score key we can get a 0 instead.

So instead of doing this (or something similar):

score = None
try:
    score = dictionary["score"]
except KeyError:
    score = 0

We can do this:

score = dictionary.get("score", 0)
# score = 0

Answer 3

Based on usage should use this get method.

Example1

In [14]: user_dict = {'type': False}

In [15]: user_dict.get('type', '')

Out[15]: False

In [16]: user_dict.get('type') or ''

Out[16]: ''

Example2

In [17]: user_dict = {'type': "lead"}

In [18]: user_dict.get('type') or ''

Out[18]: 'lead'

In [19]: user_dict.get('type', '')

Out[19]: 'lead'

Answer 4

The purpose is that you can give a default value if the key is not found, which is very useful

dictionary.get("Name",'harry')