Operator overloading: representasi string

Pemrograman Berorientasi Objek di Python

Alex Yarosh

Content Quality Analyst @ DataCamp

Mencetak objek

class Customer:
  def __init__(self, name, balance):
    self.name, self.balance = name, balance 

cust = Customer("Maryam Azar", 3000)
print(cust)

<__main__.Customer at 0x1f8598e2240>

import numpy as np

arr = np.array([1,2,3])
print(arr)

[1 2 3]

`str()`

print(obj), str(obj)

print(np.array([1,2,3]))

[1 2 3]

str(np.array([1,2,3]))

[1 2 3]

informal, untuk pengguna akhir
representasi string

`repr()`

repr(obj), mencetak di konsol

repr(np.array([1,2,3]))

array([1,2,3])

np.array([1,2,3])

array([1,2,3])

formal, untuk pengembang
representasi reproducible representation
cadangan untuk print()

Implementasi: str

class Customer:
  def __init__(self, name, balance):
    self.name, self.balance = name, balance 

  def __str__(self):
    cust_str = """
    Customer:
      name: {name}
      balance: {balance}
    """.format(name = self.name, \
               balance = self.balance)
    return cust_str

cust = Customer("Maryam Azar", 3000)

# Akan memanggil __str__() secara implisit
print(cust)

Customer:
  name: Maryam Azar
  balance: 3000

Implementasi: repr

class Customer:
  def __init__(self, name, balance):
    self.name, self.balance = name, balance 

  def __repr__(self):
    # Perhatikan '...' di sekitar name 
    return "Customer('{name}', {balance})".format(name = self.name, balance = self.balance)

cust = Customer("Maryam Azar", 3000)
cust # <--- # Akan memanggil __repr__() secara implisit

Customer('Maryam Azar', 3000) # <--- bukan Customer(Maryam Azar, 3000)

Kelilingi argumen string dengan tanda kutip dalam output __repr__()

Mari berlatih!

Pemrograman Berorientasi Objek di Python