Python collections.UserList
The class UserList in Python acts as a wrapper around a list-objects. This class is useful when one wants to create a list of their own with some modified functionality. In other words, it can be considered as a way of adding new behaviours to the list. This class takes a list instance as an argument and simulates a list that is kept in a regular list. So, the list is accessible by the data attribute of this class.
Syntax :
The signature for the UserList is as shown below.
collections.UserList([list])
Python UserList Examples:
Example 1: In this example, we will create a UserList using the existing list object. In this case, the list is now available as an attribute.
#Importing UserList
from collections import UserList
#Initializing
data = ['Delhi', 'Madhya Pradesh','Maharashtra']
ud = UserList(data)
print(ud.data)
Output
['Delhi', 'Madhya Pradesh','Maharashtra']
Example 2: In this case, we will create a UserList wherein it acts as a wrapper class for a customized list object. Thus, it will let us update attributes to the existing list to the UserList.
#Importing UserList
from collections import UserList
class info(UserList):
def replace(self, s = None,r=None):
self.append(r)
self.remove(s)
o = info([100,200,300])
print(o)
#changing value in list
o.replace(200,"India")
print(o)
Output
[100, 200, 300]
[100, 300, 'India']
Example 3: In this case, we will create a UserList wherein it acts as a wrapper class for a customized list object. Thus, it will let us delete attributes to the existing list to the UserList.
#Importing UserList
from collections import UserList
#Defining class
class info(UserList):
def deletevalue(self, s = None):
self.remove(s)
#Creating object
o = info([100,200,300])
print(o)
#deleting value
o.deletevalue(200)
print(o)
Output
[100, 200, 300]
[100, 300]
References
Happy Learning 🙂
