Python变量在功能上没有更新

class car(): 
    def __init__(self,make,model,year,fuel_capacity,perkilometer): 
     self.make = make 
     self.model = model 
     self.year = year 
     self.fuel_capacity = fuel_capacity 
     self.perkilometer = perkilometer 

     self.fuel_level = 0 

    def fill_tank(self): 
     """fills the tank full capacity""" 
     self.fuel_level = self.fuel_capacity 
     print 'Tank is Full' 

    def drive(self): 
     """drives untill out of gas""" 
     print 'car is moving' 
     i = 0 

     while 0 <= self.fuel_level: 

      self.fuel_level -= self.perkilometer 
      print '%s kilometres' % (self.fuel_level-(self.fuel_level-i)) 
      i+=1 

     print 'out of gas' 

    def travel(self,kilometer): 
     """travels for distance given""" 
     self.kilometer = kilometer 
     print 'Car is moving' 
     i=0 

     while 0!=kilometer: 
      kilometer-=1 

      i+=1 

      if self.fuel_level >= self.perkilometer: 
       self.fuel_level -= self.perkilometer 
       print '%s kilometres' % (kilometer - (kilometer - i)) 

      elif self.fuel_level < self.perkilometer: 
       self.fuel_level=0 
       print 'Out of Gas' 
       return 0 

      elif self.fuel_level == 0: 
       print 'Out of Gas' 
       return 0 

     print 'Reached to destination' 

    def continue_driving(self): 
     distance_left = self.kilometer - self.fuel_level/self.perkilometer 
     leters_needed = distance_left * self.perkilometer 

     if distance_left<=self.fuel_level/self.perkilometer: 
      print 'Have enough gas to continue' 

     else: 
      print 'Need %s leter more'% leters_needed 


    def update_fuel_level(self,new_level): 
     if new_level <= self.fuel_capacity: 
      self.fuel_level = new_level 
      print 'Tank has %s leters' % self.fuel_level 
     else: 
      print "Tank can't hold that much" 


    def add_fuel(self,amount): 
     """adds fuel to gas tank""" 

     if self.fuel_level+amount<=self.fuel_capacity: 
      self.fuel_level+=amount 
      print 'Added fuel %s leters '%amount 

     else: 
      print "Tank won't hold that much" 

#somehow fuel level is not updating after or in add_fuel func. 

my_car = car('hyundai','i20','2016','45',0.083) 
my_car.fuel_level = 2 
my_car.travel(50) 
my_car.add_fuel(1) 
my_car.continue_driving()

OUTPUT：Python变量在功能上没有更新

Car is moving 
1 kilometres 
2 kilometres 
3 kilometres 
4 kilometres 
5 kilometres 
6 kilometres 
7 kilometres 
8 kilometres 
9 kilometres 
10 kilometres 
11 kilometres 
12 kilometres 
13 kilometres 
14 kilometres 
15 kilometres 
16 kilometres 
17 kilometres 
18 kilometres 
19 kilometres 
20 kilometres 
21 kilometres 
22 kilometres 
23 kilometres 
24 kilometres 
Out of Gas 
Added fuel 1 leters 
Need 3.15 leter more

我在Python做这个车，但是当我用continue_driving方法好像fuel_level没有更新找不到错误。

主要是我正在努力实现的是计算如果油箱中的气体足够或不用于乘坐如果不加油箱。

正如你可以看到，当我运行这段代码，它说我们需要3.15升以上，但它应该是8.3/2 - （1 + 2）= 2.15

来源

2017-06-16 Suheyb Becerek

leters_needed没有考虑目前的燃料量考虑在内。你总共需要3.15，这就是它打印的内容。您需要从中减去当前的燃油量，以获得更多的燃油需求。 –

当您用完气体时，您将self.fuel_level设置为0.然后添加1升。然后，您计算出的距离为50 - 1/0.083〜= 38。然后，您计算所需公升为38 * 0.083 = 3.154。查看我的答案以获取更多细节和解决方案。 – Joshua

你是不是跟踪移动的距离。

您正试图根据您消耗的燃料和每公里的升数来计算您的距离。

distance_left = self.kilometer - self.fuel_level/self.perkilometer

你的代码是用它来计算distance_left前增加self.fuel_level。

my_car.add_fuel(1) # Increased self.fuel_level 
my_car.continue_driving() # Use self.fuel_level to determine distance_left

我建议你跟踪旅行的距离。

def __init__(self,make,model,year,fuel_capacity,perkilometer): 
    self.make = make 
    self.model = model 
    self.year = year 
    self.fuel_capacity = fuel_capacity 
    self.perkilometer = perkilometer 

    self.fuel_level = 0 
    self.distance_traveled = 0

则每次增加它你旅行

if self.fuel_level >= self.perkilometer: 
    self.fuel_level -= self.perkilometer 
    self.distance_traveled += 1 
    print '%s kilometres' % self.distance_traveled

来源

2017-06-16 20:01:49 Joshua

Python变量在功能上没有更新

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