`TypeError：一元+的错误操作数类型：'str'

Question

我的程序运行，但是输入答案后，我仍然收到错误消息

“ TypeError：一元+的错误操作数类型：'str'

def calculateCaloriesFromFat(fatGrams):
    caloriesFromFat = fatGrams * 9
    return caloriesFromFat


def calculateCaloriesFromCarbs(carbGrams):
    caloriesFromCarbs = carbGrams * 4
    return caloriesFromCarbs
  

def main():
    userFatGrams = float(input("How many Fat Grams?"))
    userCarbGrams = float(input("How many Carb Grams?"))

    caloriesFromFat = calculateCaloriesFromFat(userFatGrams)
    caloriesFromCarbs = calculateCaloriesFromCarbs(userCarbGrams)

    print("calories from fat", + format(caloriesFromFat, "f"),
          "calories from carbs", + format(caloriesFromCarbs, "f"))


main()

Answer 1

您在这里不需要+标记：

print("calories from fat", format(caloriesFromFat, "f"),
      "calories from carbs", format(caloriesFromCarbs, "f"))

Answer 2

以下方法应该起作用：

def calculateCaloriesFromFat(fatGrams):
    caloriesFromFat = fatGrams * 9
    return caloriesFromFat


def calculateCaloriesFromCarbs(carbGrams):
    caloriesFromCarbs = carbGrams * 4
    return caloriesFromCarbs

def main():
    userFatGrams = float(input("How many Fat Grams?"))
    userCarbGrams = float(input("How many Carb Grams?"))

    caloriesFromFat = calculateCaloriesFromFat(userFatGrams)
    caloriesFromCarbs = calculateCaloriesFromCarbs(userCarbGrams)

    print("calories from fat " + format(caloriesFromFat, "f") + "calories from carbs " + format(caloriesFromCarbs, "f"))

main()

但是，请考虑将format(caloriesFromFat, "f")更改为：

print("calories from fat " + str(caloriesFromFat) + " calories from carbs " + str(caloriesFromCarbs))

这样做，您将消除不需要的任何额外零。