[英]how to assign Class Instance to a variable and use that in other class
我正在为 Python 做一些基本练习。 在这里,我定义了 3 个类。 现在,我需要在另一个类中传递第一类的实例并在最后一个类中使用它。
我写了如下代码:
#defining first class:
class MobileInventory:
def __init__(self, inventory=None):
if inventory == None:
balance_inventory = {}
elif not isinstance(inventory, dict):
raise TypeError("Input inventory must be a dictionary")
elif not (set(map(type, inventory)) == {str}):
raise ValueError("Mobile model name must be a string")
elif [True for i in inventory.values() if (not isinstance(i, int) or i < 1)]:
raise ValueError("No. of mobiles must be a positive integer")
self.balance_inventory = inventory
# class to add elements to existing dictionary of above class
class add_stock:
def __init__(self, m, new_stock):
if not isinstance(new_stock, dict):
raise TypeError("Input stock must be a dictionary")
elif not (set(map(type, new_stock)) == {str}):
raise ValueError("Mobile model name must be a string")
elif [True for i in new_stock.values() if (not isinstance(i, int) or i < 1)]:
raise ValueError("No. of mobiles must be a positive integer")
for key, value in new_stock.items():
if key in m.balance_inventory.keys():
x = m.balance_inventory[key] + value
m.balance_inventory[key] = x
else:
m.balance_inventory.update({key: value})
#class to testing the above functionality
class Test_Inventory_Add_Stock:
m = ''
def setup_class():
m = MobileInventory({'iPhone Model xy': 100, 'Xiaomi Model YA': 1000, 'Nokia Model Zs': 25})
print(m.balance_inventory) # giving Output {'iPhone Model xy': 100, 'Xiaomi Model YA': 1000, 'Nokia Model Zs': 25}
def test_add_new_stock_as_dict():
add_stock( m, {'iPhone Model X': 50, 'Xiaomi Model Y': 2000, 'Nokia Model A': 10})
Test_Inventory_Add_Stock.setup_class()
Test_Inventory_Add_Stock.test_add_new_stock_as_dict()
上面我为 test_add_new_stock_as_dict 方法给出了错误“NameError: name 'm' is not defined'。
当我在课堂上宣布时,为什么不带 m? 如何在 add_stock 类中直接使用 MobileInventory.balance_inventory? 我试过它给出错误。
预期:我需要删除 NameError。 以及在没有实例的情况下直接在类中使用 MobileInventory.balance_inventory(即另一个类引用)的任何方式
Python 变量名范围更喜欢本地范围而不是外部范围,因此您需要告诉解释器m
来自哪里。
在第一种和第二种方法中,您都可以使用Test_Inventory_Add_Stock.m
来引用您的静态类变量m
。
class Test_Inventory_Add_Stock:
m = ''
def setup_class():
Test_Inventory_Add_Stock.m = MobileInventory({'iPhone Model xy': 100, 'Xiaomi Model YA': 1000, 'Nokia Model Zs': 25})
print(m.balance_inventory) # giving Output {'iPhone Model xy': 100, 'Xiaomi Model YA': 1000, 'Nokia Model Zs': 25}
def test_add_new_stock_as_dict():
add_stock(Test_Inventory_Add_Stock.m, {'iPhone Model X': 50, 'Xiaomi Model Y': 2000, 'Nokia Model A': 10})
但这看起来不太好。 要将变量限制在类的实例中,请尝试以下操作:
class Test_Inventory_Add_Stock:
def setup_class(self):
self.m = MobileInventory({'iPhone Model xy': 100, 'Xiaomi Model YA': 1000, 'Nokia Model Zs': 25})
print(m.balance_inventory) # giving Output {'iPhone Model xy': 100, 'Xiaomi Model YA': 1000, 'Nokia Model Zs': 25}
def test_add_new_stock_as_dict(self):
add_stock(self.m, {'iPhone Model X': 50, 'Xiaomi Model Y': 2000, 'Nokia Model A': 10})
t = Test_Inventory_Add_Stock()
t.setup_class()
t.test_add_new_stock_as_dict()
并且为了测试这个使用这个库 from proj.inventory import MobileInventory, InsufficientException import pytest
类 TestingInventoryCreation():
def test_creating_empty_inventory(self):
c1 = MobileInventory()
assert c1.balance_inventory == {}
def test_creating_specified_inventory(self):
c2 = MobileInventory({'iPhone Model X':100, 'Xiaomi Model Y': 1000, 'Nokia Model Z':25})
assert c2.balance_inventory == {'iPhone Model X':100, 'Xiaomi Model Y': 1000, 'Nokia Model Z':25}
#{'iPhone Model X':100, 'Xiaomi Model Y': 1000, 'Nokia Model Z':25}
def test_creating_inventory_with_list(self):
#c3 = MobileInventory(['iPhone Model X', 'Xiaomi Model Y', 'Nokia Model Z'])
with pytest.raises(TypeError) :
c3 = MobileInventory(['iPhone Model X', 'Xiaomi Model Y', 'Nokia Model Z'])
def test_creating_inventory_with_numeric_keys(self):
#c4 = MobileInventory({1:'iPhone Model X', 2:'Xiaomi Model Y', 3:'Nokia Model Z'})
with pytest.raises(ValueError):
c4 = MobileInventory({1:'iPhone Model X', 2:'Xiaomi Model Y', 3:'Nokia Model Z'})
def test_creating_inventory_with_nonnumeric_values(self):
#c5 = MobileInventory({'iPhone Model X':'100', 'Xiaomi Model Y': '1000', 'Nokia Model Z':'25'})
with pytest.raises(ValueError):
c5 = MobileInventory({'iPhone Model X':'100', 'Xiaomi Model Y': '1000', 'Nokia Model Z':'25'})
def test_creating_inventory_with_negative_value(self):
#c6 = MobileInventory({'iPhone Model X':-45, 'Xiaomi Model Y': 200, 'Nokia Model Z':25})
with pytest.raises(ValueError) :
c6 = MobileInventory({'iPhone Model X':-45, 'Xiaomi Model Y': 200, 'Nokia Model Z':25})
类 TestInventoryAddStock(): 库存 = 无
@classmethod
def setup_class(cls):
cls.inventory = MobileInventory({'iPhone Model X': 100, 'Xiaomi Model Y': 1000, 'Nokia Model Z':25})
def test_add_new_stock_as_dict(self):
self.inventory.add_stock({'iPhone Model X': 50, 'Xiaomi Model Y': 2000, 'Nokia Model A': 10})
assert self.inventory.balance_inventory == {'iPhone Model X': 150, 'Xiaomi Model Y': 3000, 'Nokia Model Z': 25, 'Nokia Model A': 10}
def test_add_new_stock_as_list(self):
with pytest.raises(TypeError) :
MobileInventory.add_stock(['iPhone Model X', 'Xiaomi Model Y', 'Nokia Model Z'])
def test_add_new_stock_with_numeric_keys(self):
with pytest.raises(ValueError):
MobileInventory.add_stock({1:'iPhone Model A', 2:'Xiaomi Model B', 3:'Nokia Model C'})
def test_add_new_stock_with_nonnumeric_values(self):
with pytest.raises(ValueError):
MobileInventory.add_stock({'iPhone Model A':'50', 'Xiaomi Model B': '2000', 'Nokia ModelC':'25'})
def test_add_new_stock_with_float_values(self):
with pytest.raises(ValueError):
MobileInventory.add_stock({'iPhone Model A':50.5, 'Xiaomi Model B':2000.3, 'Nokia Model C':25})
类 TestInventorySellStock(): 库存 = 无
@classmethod
def setup_class(cls):
cls.inventory = MobileInventory(
{'iPhone Model A': 50, 'Xiaomi Model B': 2000, 'Nokia Model C': 10, 'Sony Model D': 1})
def test_sell_stock_as_dict(self):
self.inventory.sell_stock({'iPhone Model A': 2, 'Xiaomi Model B': 20, 'Sony Model D': 1})
assert self.inventory.balance_inventory == {'iPhone Model A': 48, 'Xiaomi Model B': 1980, 'Nokia Model C': 10,
'Sony Model D': 0}
def test_sell_stock_as_list(self):
with pytest.raises(TypeError):
MobileInventory.sell_stock(['iPhone Model A', 'Xiaomi Model B', 'Nokia Model C'])
def test_sell_stock_with_numeric_keys(self):
with pytest.raises(ValueError):
MobileInventory.sell_stock({1: 'iPhone Model A', 2: 'Xiaomi Model B', 3: 'Nokia Model C'})
def test_sell_stock_with_nonnumeric_values(self):
with pytest.raises(ValueError):
MobileInventory.sell_stock({'iPhone Model A': '5', 'Xiaomi Model B': '3', 'Nokia Model C': '4'})
def test_sell_stock_with_float_values(self):
with pytest.raises(ValueError):
MobileInventory.sell_stock({'iPhone Model A': 2.5, 'Xiaomi Model B': 3.1, 'Nokia Model C': 4})
def test_sell_stock_of_nonexisting_model(self):
with pytest.raises(InsufficientException):
MobileInventory.sell_stock({'iPhone Model B': 2, 'Xiaomi Model B': 5})
def test_sell_stock_of_insufficient_stock(self):
with pytest.raises(InsufficientException):
MobileInventory.sell_stock({'iPhone Model A': 2, 'Xiaomi Model B': 5, 'Nokia Model C': 15})
def test_sell_stock_of_nonexisting_model(self):
with pytest.raises(InsufficientException):
MobileInventory.sell_stock({'iPhone Model B': 2, 'Xiaomi Model B': 5})
def test_sell_stock_of_insufficient_stock(self):
with pytest.raises(InsufficientException):
MobileInventory.sell_stock({'iPhone Model A': 2, 'Xiaomi Model B': 5, 'Nokia Model C': 15})
类型错误:sell_stock() 缺少 1 个必需的位置参数:'requested_stock'
我猜下面是在运行 Pytests 时定义类属性的预期方式。
class TestInventoryAddStock:
@classmethod
def setup_class(cls):
cls.inventory = MobileInventory({'iPhone Model X':100, 'Xiaomi Model Y': 1000, 'Nokia Model Z':25})
def test_add_new_stock_as_dict(self):
self.inventory.add_stock({'iPhone Model X':50, 'Xiaomi Model Y': 2000, 'Nokia Model A':10})
assert self.inventory.balance_inventory == {'iPhone Model X':150, 'Xiaomi Model Y': 3000, 'Nokia Model Z':25, 'Nokia Model A':10}
class InsufficientException(Exception):
pass
class MobileInventory:
balance_inventory = {}
def __init__(self, inventory=None):
if not inventory:
MobileInventory.balance_inventory = {}
else:
if not isinstance(inventory, dict):
raise TypeError("Input inventory must be a dictionary")
elif not (set(map(type, inventory)) == {str}):
raise ValueError("Mobile model name must be a string")
else:
for i in inventory.values():
if isinstance(i, int) and i > 0:
pass
else:
raise ValueError("No. of mobiles must be a positive integer")
MobileInventory.balance_inventory = inventory
@classmethod
def add_stock(cls, new_stock):
print("before update")
print(cls.balance_inventory)
if not isinstance(new_stock, dict):
raise TypeError("Input stock must be a dictionary")
elif not (set(map(type, new_stock)) == {str}):
raise ValueError("Mobile model name must be a string")
else:
for i in new_stock.values():
if isinstance(i, int) and i > 0:
pass
else:
raise ValueError("No. of mobiles must be a positive integer")
for key, value in new_stock.items():
if key in cls.balance_inventory.keys():
x = cls.balance_inventory[key] + value
cls.balance_inventory[key] = x
else:
cls.balance_inventory.update({key: value})
print(new_stock)
print("after update")
print(cls.balance_inventory)
@classmethod
def sell_stock(cls, requested_stock):
if not isinstance(requested_stock, dict):
raise TypeError("Requested stock must be a dictionary")
elif not (set(map(type, requested_stock)) == {str}):
raise ValueError("Mobile model name must be a string")
else:
for i in requested_stock.values():
if isinstance(i, int) and i > 0:
pass
else:
raise ValueError("No. of mobiles must be a positive integer")
for key, value in requested_stock.items():
if key in cls.balance_inventory.keys():
if cls.balance_inventory[key] < value:
raise InsufficientException("Insufficient Stock")
else:
y = cls.balance_inventory[key] - value
cls.balance_inventory[key] = y
else:
raise InsufficientException("No Stock. New Model Request")
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