why Python data classes

example_csv_manipulation.py

import csv
from dataclasses import dataclass

"""
Creer une classe personne representant chaque ligne du fichier csv
"""

class Person2:
    def __init__(self, list_name, name, label, agence, nom_prenom_cli, type_cli, anon):
        self.list_name = list_name
        self.name = name
        self.label = label
        self.agence = agence
        self.nom_prenom_cli = nom_prenom_cli
        self.type_cli = type_cli
        self.anon = anon


# an example of what you may encounter in your career: a class with a lot of attributes
class Person3:
    def __init__(self, list_name, name, label, agence, nom_prenom_cli, type_cli, anon, adress, location, email1, email2, phone1, phone2):
        self.list_name = list_name
        self.name = name
        self.label = label
        self.agence = agence
        self.nom_prenom_cli = nom_prenom_cli
        self.type_cli = type_cli
        self.anon = anon
        self.email1 = email1
        self.email2 = email2
        self.phone1 = phone1
        self.phone2 = phone2


# data classes, are the way for you to easily or quickly define a class without writing too much code
# a __init__ will be generated for you
@dataclass
class Person4:
    list_name: str # keep in mind, every attribute should have a type
    name: str
    label: str
    agence: str
    nom_prenom_cli: str
    type_cli: str
    anon: str
    email1: str
    email2: str
    phone1: str
    phone2: str



# a class to represetn a person
class OldPerson:
    def __init__(self, lst):
        # here we don't know what are the item inside the list
        # so we are better put a verification
        assert len(lst) == 7 # a tiny tiny verification
        self.list_name = lst[0]
        self.name = lst[1]
        self.label = lst[2]
        self.agence = lst[3]
        self.nom_prenom_cli = lst[4]
        self.type_cli = lst[5]
        self.anon = lst[6]

    def __eq__(self, other):
        return self.name == other.name


# thanks to dataclasses
# you will have for free
# __init__
# __repr__ that can be reimplemented if you need to
# __eq__  that can be reimplemented if you need to

@dataclass
class Person:
    list_name: str = "foo" # int, float, str, List, Dict, Tuple, Set
    name: str = "bar"
    label: str = "baz"
    agence: str = "corge"
    nom_prenom_cli: str = "qux"
    type_cli: str = "quux"
    anon: str = "warlow"

    # you can add methods if you want
    # but keep in mind most the time it is not what you'll need
    def dire_bonjour(self):
        return 42


# a list containing all the persons
results = []

# the csv file to open
monFichier = open('clients.csv','r')
data = csv.reader(monFichier, delimiter=',')

# a for loop to read each line of the csv file
for line in data:
    results.append(Person())

p6 = results[6]
p10 = results[10]

print(p6)
print(p10)

print(p10.name)
print(p6.name)
print(p10 == p6)


# example of a method call that behaves as usual
print(p10.dire_bonjour())