بايثون المتوسط: البرمجة الشيئية في الممارسة - الكود والأوامر التي تهم حقاً

class CompteBancaire:
    def __init__(self, titulaire, solde):
        self.titulaire = titulaire        # عام
        self._solde = solde               # اصطلاح: لا تلمسه
        self.__pin = "1234"                # خاص (name mangling)

c = CompteBancaire("Alice", 1000)
print(c.titulaire)                  # OK
print(c._solde)                     # يمكن الوصول إليه لكنه غير مستحسن
# print(c.__pin)                    # AttributeError !
print(c._CompteBancaire__pin)       # يمكن الوصول إليه بالاسم المعدل

class Temperature:
    def __init__(self, celsius):
        self.celsius = celsius

t = Temperature(25)
t.celsius = -500          # غير منطقي!
print(t.celsius)          # -500

class Temperature:
    def __init__(self, celsius):
        self._celsius = celsius

    @property
    def celsius(self):
        return self._celsius

    @celsius.setter
    def celsius(self, valeur):
        if valeur < -273.15:
            raise ValueError("تحت الصفر المطلق، مستحيل")
        self._celsius = valeur

t = Temperature(25)
print(t.celsius)            # 25 (يستدعي الـgetter)
t.celsius = 30              # يستدعي الـsetter، OK
t.celsius = -300            # ValueError !

class Cercle:
    def __init__(self, rayon):
        self.rayon = rayon

    @property
    def diametre(self):
        return self.rayon * 2

    @property
    def aire(self):
        from math import pi
        return pi * self.rayon ** 2

c = Cercle(5)
print(c.diametre)         # 10
print(c.aire)             # 78.539...
# c.aire = 100            # AttributeError : لا يوجد setter

class Personne:
    def __init__(self, nom):
        self._nom = nom

    @property
    def nom(self):
        return self._nom

    @nom.setter
    def nom(self, valeur):
        if not isinstance(valeur, str) or len(valeur) < 2:
            raise ValueError("اسم غير صالح")
        self._nom = valeur.title()      # تطبيع

    @nom.deleter
    def nom(self):
        print("حذف الاسم")
        self._nom = None

p = Personne("alice")
print(p.nom)              # Alice (مطبّع)
p.nom = "bob"
print(p.nom)              # Bob
del p.nom                 # حذف الاسم

class CompteBancaire:
    def __init__(self, titulaire, solde=0):
        self.titulaire = titulaire
        self._solde = 0
        self.solde = solde         # يمر عبر الـsetter!

    @property
    def solde(self):
        return self._solde

    @solde.setter
    def solde(self, valeur):
        if valeur < 0:
            raise ValueError("رصيد سالب ممنوع")
        self._solde = valeur

    def deposer(self, montant):
        if montant <= 0:
            raise ValueError("يجب أن يكون المبلغ موجبًا")
        self.solde += montant       # يمر عبر الـsetter

    def retirer(self, montant):
        if montant > self._solde:
            raise ValueError("رصيد غير كافٍ")
        self.solde -= montant

c = CompteBancaire("Alice", 1000)
c.deposer(500)
print(c.solde)            # 1500
# c.solde = -100          # ValueError

class Animal:
    def __init__(self, nom, age):
        self.nom = nom
        self.age = age

    def manger(self):
        print(f"{self.nom} mange")

    def dormir(self):
        print(f"{self.nom} dort")


class Chien(Animal):
    def aboyer(self):
        print(f"{self.nom} : Wouaf !")


rex = Chien("Rex", 5)
rex.manger()              # موروث من Animal
rex.dormir()              # موروث من Animal
rex.aboyer()              # خاص بـChien
print(rex.age)            # موروث

class Animal:
    def parler(self):
        print("Bruit générique d’animal")


class Chien(Animal):
    def parler(self):
        print("Wouaf !")


class Chat(Animal):
    def parler(self):
        print("Miaou")


for a in [Chien(), Chat(), Animal()]:
    a.parler()
# Wouaf !
# Miaou
# Bruit générique d’animal

class Animal:
    def __init__(self, nom, age):
        self.nom = nom
        self.age = age

    def description(self):
        return f"{self.nom}, {self.age} ans"


class Chien(Animal):
    def __init__(self, nom, age, race):
        super().__init__(nom, age)        # يستدعي Animal.__init__
        self.race = race

    def description(self):
        base = super().description()       # يستدعي Animal.description
        return f"{base}, race {self.race}"


rex = Chien("Rex", 5, "Labrador")
print(rex.description())     # Rex, 5 ans, race Labrador

rex = Chien("Rex", 5, "Labrador")

print(isinstance(rex, Chien))      # True
print(isinstance(rex, Animal))     # True (وراثة)
print(isinstance(rex, Chat))       # False

print(issubclass(Chien, Animal))   # True
print(issubclass(Animal, Chien))   # False

class Livre:
    def __init__(self, titre, auteur, isbn):
        self.titre = titre
        self.auteur = auteur
        self.isbn = isbn
        self.disponible = True

    def description(self):
        return f"{self.titre} de {self.auteur}"


class Roman(Livre):
    def __init__(self, titre, auteur, isbn, genre):
        super().__init__(titre, auteur, isbn)
        self.genre = genre

    def description(self):
        return f"{super().description()} -- roman {self.genre}"


class LivreNumerique(Livre):
    def __init__(self, titre, auteur, isbn, format_fichier):
        super().__init__(titre, auteur, isbn)
        self.format_fichier = format_fichier

    def telecharger(self):
        print(f"Téléchargement de {self.titre}.{self.format_fichier}")


dune = Roman("Dune", "Herbert", "978...", "science-fiction")
ebook = LivreNumerique("1984", "Orwell", "978...", "epub")

print(dune.description())       # Dune de Herbert -- roman science-fiction
print(ebook.description())       # 1984 de Orwell
ebook.telecharger()              # Téléchargement de 1984.epub

lambda parametres: expression

def doubler(x):
    return x * 2

doubler_lambda = lambda x: x * 2

print(doubler(5))         # 10
print(doubler_lambda(5))  # 10

somme = lambda a, b: a + b
print(somme(3, 4))                       # 7

est_pair = lambda n: n % 2 == 0
print(est_pair(8))                       # True

prix = [10, 25, 7, 50]
prix_ttc = list(map(lambda p: p * 1.20, prix))
print(prix_ttc)        # [12.0, 30.0, 8.4, 60.0]

mots = ["python", "poo", "code"]
majuscules = list(map(str.upper, mots))
print(majuscules)      # ['PYTHON', 'POO', 'CODE']

a = [1, 2, 3]
b = [10, 20, 30]
sommes = list(map(lambda x, y: x + y, a, b))
print(sommes)          # [11, 22, 33]

notes = [12, 8, 15, 6, 18, 11]
reussies = list(filter(lambda n: n >= 10, notes))
print(reussies)        # [12, 15, 18, 11]

mots = ["chat", "chien", "ours", "lion"]
courts = list(filter(lambda m: len(m) <= 4, mots))
print(courts)          # ['chat', 'ours', 'lion']