我正在用Python编写一段代码来为PC建筑商店创建一个订单系统，并且有一个“订单”类，其中包含一个打印订单的方法。当我在我的一个函数中引用它（创建一个订单）（放置订单）时，它工作正常。如：
order1 = order(1,'Luke','p5','16gb','1tb','19in','midi','4usb')
但是当我在'main'函数中引用它时，它在运行代码时会出现此错误：
File "program.py", line 103, in main
order1 = order(1,'Luke','p5','16gb','1tb','19in','midi','4usb')
UnboundLocalError: local variable 'order' referenced before assignment
这对我来说毫无意义，因为它在我的其他功能中非常有效。整个代码打印在下面。你可以在'main'函数中看到在函数的第一行和第二行首先调用错误的行，以及稍后当输入文本'test'时，它也会返回错误，没有明显的原因。我在Mac OS X上使用Python 3.6.3。
#!/usr/bin/env python3
class order(object):
def __init__(self, orderNo, customer, processor, ram, storage, screen, case, usb):
self.orderNo = orderNo
self.customer = customer
self.processor = processor
self.ram = ram
self.storage = storage
self.screen = screen
self.case = case
self.usb = usb
def stockCost(self):
global componentCosts
return componentCosts[self.processor] + componentCosts[self.ram] + componentCosts[self.storage] + componentCosts[self.screen]+ componentCosts[self.case]+ componentCosts[self.usb]
def salePrice(self):
return self.stockCost() * 1.2
def print_order(self):
"""Prints the data of an order in a viewable way for the vendor"""
return 'Order number: {}, for customer: {}.\n'.format(self.orderNo, self.customer) \
+ '{} processor.\n'.format(self.processor) \
+ '{} of ram.\n'.format(self.ram.upper()) \
+ '{} of storage.\n'.format(self.storage.upper()) \
+ '{} screen.\n'.format(self.screen) \
+ '{}{} case.\n'.format(self.case.lower()[0].upper(), self.case.lower()[1:])\
+ '{} {} ports.\n'.format(self.usb[0], self.usb[1:].upper()) \
+ 'Your chosen build will cost ${:0.2f}.\n'.format(self.salePrice())
def user_print_order(self):
"""Prints the data of an order in a viewable way for the customer"""
return '{}, your order number is {}.\n'.format(self.customer, self.orderNo) \
+ 'You have chosen a {} processor.\n'.format(self.processor) \
+ 'You have chosen {} of ram.\n'.format(self.ram.upper()) \
+ 'You have chosen to have {} of storage.\n'.format(self.storage.upper()) \
+ 'You have chosen a {} screen.\n'.format(self.screen) \
+ 'You have chosen a {}{} case.\n'.format(self.case.lower()[0].upper(), self.case.lower()[1:])\
+ 'You have chosen to have {} {} ports.\n'.format(self.usb[0], self.usb[1:].upper()) \
+ 'Your chosen build will cost ${:0.2f}.\n'.format(self.salePrice())
def place_order():
global componentList
global stock
global orders
orderOK = True
componentChoices = {}
print ('Please choose your components, These are your options:\n(please enter the component as they appear on the component list)\n' + componentList)
name = input('Please enter your name: ')
componentChoices['processor'] = input('Please enter what processor you would like: ')
componentChoices['ram'] = input('Please enter how much ram you would like: ')
componentChoices['storage'] = input('Please enter how much storage you would like: ')
componentChoices['screen'] = input('Please enter how big a screen you would like: ')
componentChoices['case'] = input('Please enter what size case you would like: ')
componentChoices['usb'] = input('Please enter whether you would like 4 USB ports or 2 (enter 4USB or 2USB): ')
for part in componentChoices:
choice = componentChoices[part].lower()
if stock[choice] < 1:
print ('Your choice of {} is out of stock, please choose a different option.\n'.format(part) + componentList)
componentChoice[part] = input('Enter your new choice of {}.'.format(part))
if stock[componentChoices[part]] < 1:
print ('Your choice of {} is also out of stock, your order has thus failed to go through. Please try again later.')
orderOK = False
return None
else: stock[componentChoices[part].lower()] -= 1
toBeReturned = order(len(orders)+1, name, componentChoices['processor'], componentChoices['ram'], componentChoices['storage'], componentChoices['screen'], componentChoices['case'], componentChoices['usb'])
print (toBeReturned.user_print_order())
query = input('Is this information correct? Enter "Y" or "N".')
while True:
if query.lower() == 'y':
break
if query.lower == 'n':
print('Your order has not been placed, please re-place the order')
return None
return toBeReturned
componentList = 'Processor: p3, p5 or p7\nRAM: 16GB or 32GB\nStorage: 1TB or 2TB\nScreen: 19in or 23in\nCase Size: Mini or Midi\nNo of Ports: 2USB or 4USB'
componentCosts = {
'p3': 100, 'p5': 120, 'p7': 200, '16gb': 75, '32gb': 150,
'1tb': 50, '2tb': 100, '19in': 65, '23in': 120, 'mini': 40,
'midi': 70, '2usb': 10, '4usb': 20
}
stock = {
'p3': 100, 'p5': 100, 'p7': 100, '16gb': 100, '32gb': 100,
'1tb': 100, '2tb': 100, '19in': 100, '23in': 100, 'mini': 100,
'midi': 100, '2usb': 100, '4usb': 100
}
orders = {}
#~ order1 = order(1,'Luke','p5','16gb','1tb','19in','midi','4usb')
#~ print (order1.print_order())
def main():
order1 = order(1,'Luke','p5','16gb','1tb','19in','midi','4usb')
print (order1.print_order())
global componentList
global stock
global orders
while True:
print ('\nEnter "make" to place an order, "view" to view previous orders, "stock" to view the stock levels, and "quit" to quit the program. Quitting the program will lose records of previous orders, please back them up by copying the output from entering "view".')
command = input().lower()
while True:
if command == 'quit':
return False
if command == 'view':
for order in orders:
print (orders[order].print_order()+'\n')
break
if command == 'make':
#~ globals()["order" + str(len(orders)+1)] = place_order()
order1 = order()
if globals()["order" + str(len(orders)+1)] == None:
break
else:
orders[len(orders)+1] = globals()["order" + str(len(orders)+1)]
break
if command == 'stock':
for i in stock:
print(i + ': ' + str(stock[i]))
if command == 'test':
for i in range(10):
globals()["order" + str(i)] = order(i,'Luke','p5','16gb','1tb','19in','midi','4usb')
orders[len(orders)+1] = globals()["order" + str(i)]
else:
print('Invalid option entered please try again')
break
if __name__ == "__main__":
main()
答案 0 :(得分：1)
在main函数中，您执行循环：
for order in orders:
...
这是对order的隐藏赋值，导致编译器将order标记为局部变量，因此UnboundLocalError: local variable 'order' referenced before assignment
如@Rawing的评论中所述，如果您遵循PEP8命名约定，则可以避免这种情况。类名应该是CapitalCase。