Python變量在功能上沒有更新

Question

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：

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做這個車，但是當我用continue_driving方法好像fuel_level沒有更新找不到錯誤。

主要是我正在努力實現的是計算如果油箱中的氣體足夠或不用於乘坐如果不加油箱。

正如你可以看到，當我運行這段代碼，它說我們需要3.15升以上，但它應該是8.3/2 - （1 + 2）= 2.15

Answer 1

你是不是跟蹤移動的距離。

您正試圖根據您消耗的燃料和每公里的升數來計算您的距離。

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

你的代碼是用它來計算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 

我建議你跟蹤旅行的距離。

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 

則每次增加它你旅行

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