Python dict data type does not provide default value, which means we can not read a nonexistent key. In this tutorial, we will discuss python defaultdict, it supplies a default value for dict data type.
Python dict data type
Create a dict
member = {'age':23, 'name': 'John'}
print(member)The memeber is:
{'name': 'John', 'age': 23}Read value with nonexistent key
sex = member['sex'] print(sex)
You will get this error.
KeyError: ‘sex’
Create a python dict with default value
Import library
from collections import defaultdict
Set default value for python dict
member = defaultdict(lambda: 'male')
Add key: value for dict
member['age'] = 23 member['name'] = 'John'
Read value with key
name = member['name'] print(name)
The name is John
Read value with nonexistent key
sex = member['sex'] print(sex)
This code will return default value: male