unorderable类型：NoneType（）<NoneType（）

Question

每当我在cheapest_shipping函数中输入一个大于10的值时，它就会产生一个无法解决的类型错误。

我已经尝试将单独的变量传递给函数来计算成本。还试过不同的比较运算符。

cost = 0
pgs = 125

def gsp(weight):
  if weight == 0:
cost = 20
return cost
  elif weight <= 2:
cost = (1.5 * weight + 20)
return cost 
  elif weight > 2 and weight <= 6:
cost = (3 * weight + 20)
return cost
  elif weight > 6 and weight <= 10:
cost = (4 * weight + 20)
return cost
  elif weight > 10:
cost = (4.75 * weight + 20)

def dsp(weight):
  if weight == 0:
cost = 0
return cost
  elif weight <= 2:
cost = (4.5 * weight)
return cost 
  elif weight > 2 and weight <= 6:
cost = (9 * weight)
return cost
  elif weight > 6 and weight <= 10:
cost = (12 * weight)
return cost
  elif weight > 10:
cost = (14.25 * weight)

def cheapest_shipping(weight):
  if gsp(weight) < dsp(weight) and gsp(weight) < pgs:
return "Ground shipping is the cheapest option at $" + str(gsp(weight))
  elif dsp(weight) < gsp(weight) and dsp(weight) < pgs:
return "Drone shipping is the cheapest option at $" + str(dsp(weight))

print (cheapest_shipping(11))

该功能使用我的地面运费价格功能和无人机运费价格功能和优质地面运输的成本，并采取重量输入，并应该返回最便宜的运输选项。哪个有效，直到输入超过10。

Answer 1

在最后的return cost声明中缺少elif。这可能是你想要的

cost = 0
pgs = 125


def gsp(weight):
    if weight == 0:
        cost = 20
        return cost
    elif weight <= 2:
        cost = (1.5 * weight + 20)
        return cost
    elif weight > 2 and weight <= 6:
        cost = (3 * weight + 20)
        return cost
    elif weight > 6 and weight <= 10:
        cost = (4 * weight + 20)
        return cost
    elif weight > 10:
        cost = (4.75 * weight + 20)
        return cost


def dsp(weight):
    if weight == 0:
        cost = 0
        return cost
    elif weight <= 2:
        cost = (4.5 * weight)
        return cost
    elif 2 < weight <= 6:
        cost = (9 * weight)
        return cost
    elif 6 < weight <= 10:
        cost = (12 * weight)
        return cost
    elif weight > 10:
        cost = (14.25 * weight)
        return cost


def cheapest_shipping(weight):
    if gsp(weight) < dsp(weight) and gsp(weight) < pgs:
        return "Ground shipping is the cheapest option at $" + str(gsp(weight))
    elif dsp(weight) < gsp(weight) and dsp(weight) < pgs:
        return "Drone shipping is the cheapest option at $" + str(dsp(weight))


print (cheapest_shipping(11))