Python supports a type of container like dictionaries called “namedtuple()” present in module, “collections“. Like dictionaries they contain keys that are hashed to a particular value. But on contrary, it supports both access from key value and iteration, the functionality that dictionaries lack.
Example:
# Python code to demonstrate namedtuple() from collections import namedtuple
# Declaring namedtuple() Student = namedtuple('Student',['name','age','DOB'])
# Adding values S = Student('Nandini','19','2541997')
# Access using index print ("The Student age using index is : ",end ="")
print (S[1])
# Access using name print ("The Student name using keyname is : ",end ="")
print (S.name)
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Output:
The Student age using index is : 19 The Student name using keyname is : Nandini
Let’s see various Operations on namedtuple() :
Access Operations
- Access by index : The attribute values of namedtuple() are ordered and can be accessed using the index number unlike dictionaries which are not accessible by index.
- Access by keyname : Access by keyname is also allowed as in dictionaries.
- using getattr() :- This is yet another way to access the value by giving namedtuple and key value as its argument.
# Python code to demonstrate namedtuple() and # Access by name, index and getattr() # importing "collections" for namedtuple() import collections
# Declaring namedtuple() Student = collections.namedtuple('Student',['name','age','DOB'])
# Adding values S = Student('Nandini','19','2541997')
# Access using index print ("The Student age using index is : ",end ="")
print (S[1])
# Access using name print ("The Student name using keyname is : ",end ="")
print (S.name)
# Access using getattr() print ("The Student DOB using getattr() is : ",end ="")
print (getattr(S,'DOB'))
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Output :
The Student age using index is : 19 The Student name using keyname is : Nandini The Student DOB using getattr() is : 2541997
Conversion Operations
- _make() :- This function is used to return a namedtuple() from the iterable passed as argument.
- _asdict() :- This function returns the OrderedDict() as constructed from the mapped values of namedtuple().
- using “**” (double star) operator :- This function is used to convert a dictionary into the namedtuple().
# Python code to demonstrate namedtuple() and # _make(), _asdict() and "**" operator # importing "collections" for namedtuple() import collections
# Declaring namedtuple() Student = collections.namedtuple('Student',['name','age','DOB'])
# Adding values S = Student('Nandini','19','2541997')
# initializing iterable li = ['Manjeet', '19', '411997' ]
# initializing dict di = { 'name' : "Nikhil", 'age' : 19 , 'DOB' : '1391997' }
# using _make() to return namedtuple() print ("The namedtuple instance using iterable is : ")
print (Student._make(li))
# using _asdict() to return an OrderedDict() print ("The OrderedDict instance using namedtuple is : ")
print (S._asdict())
# using ** operator to return namedtuple from dictionary print ("The namedtuple instance from dict is : ")
print (Student(**di))
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Output :
The namedtuple instance using iterable is :
Student(name='Manjeet', age='19', DOB='411997')
The OrderedDict instance using namedtuple is :
OrderedDict([('name', 'Nandini'), ('age', '19'), ('DOB', '2541997')])
The namedtuple instance from dict is :
Student(name='Nikhil', age=19, DOB='1391997')
Additional Operations
- _fields :- This function is used to return all the keynames of the namespace declared.
- _replace() :- This function is used to change the values mapped with the passed keyname.
# Python code to demonstrate namedtuple() and # _fields and _replace() # importing "collections" for namedtuple() import collections
# Declaring namedtuple() Student = collections.namedtuple('Student',['name','age','DOB'])
# Adding values S = Student('Nandini','19','2541997')
# using _fields to display all the keynames of namedtuple() print ("All the fields of students are : ")
print (S._fields)
# using _replace() to change the attribute values of namedtuple print ("The modified namedtuple is : ")
print(S._replace(name = 'Manjeet'))
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Output :
All the fields of students are :
('name', 'age', 'DOB')
The modified namedtuple is :
Student(name='Manjeet', age='19', DOB='2541997')
This article is contributed by Manjeet Singh. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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