How to use NamedTuple and Dataclass in Python?
We have all worked with classes and objects for more than once while coding. But have you ever wondered how to create a class other than the naive methods we have all been taught. Don’t worry in this article we are going to cover these alternate methods. There are two alternative ways to construct a class in Python.
First, of all let’s create a class with the naive methods. Let’s create a class transaction, where each payment transaction has a sender, a receiver, date, and the amount.
Example:
Python
class Transaction:
def __init__( self , amount, sender, receiver, date):
self .amount = amount
self .sender = sender
self .receiver = receiver
self .date = date
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This is pretty straight forward but let’s be honest this is a lot of code for us lazy developers. Now, this is where NamedTuple comes in.
Using NamedTuple
Named Tuple is essentially an extension of the Python built-in tuple data type. Python’s tuple is a simple data structure for grouping objects with different types. Its defining feature is being immutable i.e an object whose state cannot be modified after it is created.
We will start with the collections package. This package provides alternatives to Python’s general built-in types like dict, list, set, and tuple. Creating a NamedTuple object is as straightforward as creating the class.
Python3
import collections
Transaction = collections.namedtuple( 'Transaction' ,
[ 'sender' , 'amount' ,
'receiver' , 'date' ])
record = Transaction(sender = "Aryaman" ,
receiver = "Ankur" ,
date = "2020-06-18" ,
amount = 1.0 )
print (record)
print (record.receiver)
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Output:
Transaction(sender=’Aryaman’, amount=1.0, receiver=’Ankur’, date=’2020-06-18′)
Ankur
Using DataClass
DataClass may be a new feature introduced since Python 3.7. It is used as a decorator. What it does under the hood is implementing __init__, __repr__, etc for us.
Example:
Python3
from dataclasses import dataclass
@dataclass
class Transaction:
sender: str
receiver: str
date: str
amount: float
record = Transaction(sender = "Aryaman" ,
receiver = "Ankur" ,
date = "2020-06-18" ,
amount = 1.0 )
print (record)
print (record.receiver)
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Output:
Transaction(sender=’Aryaman’, receiver=’Ankur’, date=’2020-06-18′, amount=1.0)
Ankur
NamedTuple behaves like a tuple, while DataClass behaves more like a regular Python class because by default, the attributes are all mutable and they can only be accessed by name, not by index.
Last Updated :
26 Jul, 2020
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