Question

我对Python编程很陌生，今年刚刚开始。我目前正在围绕python中的函数做一个项目，而且我遇到了问题。继承了我到目前为止所做的事情，但它却陷入了第三个定义。

def userWeight():
    weight = input("Enter your weight in pounds:")

def userHeight():
    height = input("Enter your height in inches:")

def convertWeightFloat(weight):
    return float(weight)
    weight = float(weight)

def convertHeightFloat(hf):
    return float(height)

def calculateBMI():
    BMI = (5734 * weight_float) / (height_float**2.5)
    return BMI

def displayBMI():
    print("Your BMI is:",BMI)

def convertKG():
   return weight_float * .453592

def convertM():
    return height_float * .0254

def calculateBMImetric():
    return 1.3 * weight_kg / height_meters**2.5

def displayMetricBMI():
    print("Your BMI using Metric calculations is: ", BMImetric)

def main():
    userWeight()
    userHeight()
    convertWeightFloat(weight)
    convertHeightFloat()
    calculateBMI()
    displayBMI()
    convertKG()
    convertM()
    calculateBMImetric()
    displayMetricBMI()

main()

这是我每次尝试运行时收到的错误消息......

Enter your weight in pounds:155
Enter your height in inches:70
Traceback (most recent call last):
  File "C:/Users/Julian/Desktop/Python Stuff/ghp17.py", line 45, in <module>
    main()
  File "C:/Users/Julian/Desktop/Python Stuff/ghp17.py", line 36, in main
    convertWeightFloat(weight)
NameError: name 'weight' is not defined

现在我可能尝试了几种不同的东西，每种东西都给我不同的错误。

任何帮助人员？

Answer 1

在main函数中，您传递的是weight，但尚未对其进行定义。您可能希望保存userWeight：

中的值

def userWeight():
    weight = input("Enter your weight in pounds:")
    return weight

def main():
    weight = userWeight()
    ...
    convertWeightFloat(weight)

在计算之前，您还会返回weight：

def convertWeightFloat(weight):
    return float(weight)
    weight = float(weight)

计算后移动return语句：

def convertWeightFloat(weight):
    weight = float(weight)
    return float(weight)

Answer 2

这里有一些问题。

首先，在convertWeightFloat(weight)尚未定义的情况下，您致电weight。这是因为weight仅存在于您的函数userWeight中（它被称为函数的范围）。如果您希望在程序的主要部分中知道weight，则需要在那里定义它。

weight = userWeight()
...

仅当函数userWeight返回值时才有效：

def userWeight():
    weight = input("Enter your weight in pounds:")
    return weight

与height相同的问题。

此外，在函数convertWeightFloat中，return语句是将要执行的最后一件事。在该行之后，程序退出该函数，从而永远不会执行最后一行：

def convertWeightFloat(weight):
    weight = float(weight)
    return weight

基本上，您在函数内使用的每个变量都应该提供给函数（大多数时候作为参数）。并且您的所有函数都应返回已处理的值。这是您的程序的工作版本：

def userWeight():
    weight = input("Enter your weight in pounds:")
    return weight

def userHeight():
    height = input("Enter your height in inches:")
    return height

def convertWeightFloat(weight):
    return float(weight)

def convertHeightFloat(height):
    return float(height)

def calculateBMI(weight_float, height_float):
    BMI = (5734 * weight_float) / (height_float**2.5)
    return BMI

def displayBMI(BMI):
    print("Your BMI is:",BMI)

def convertKG(weight_float):
   return weight_float * .453592

def convertM(height_float):
    return height_float * .0254

def calculateBMImetric(weight_kg, height_meters):
    return 1.3 * weight_kg / height_meters**2.5

def displayMetricBMI(BMImetric):
    print("Your BMI using Metric calculations is: ", BMImetric)

def main():
    weight = userWeight()
    height = userHeight()
    weight_float = convertWeightFloat(weight)
    height_float = convertHeightFloat(height)
    bmi = calculateBMI(weight_float, height_float)
    displayBMI(bmi)

Answer 3

在你打电话的主（）中

convertWeightFloat（重量）

但没有定义重量

在函数中未定义回溯和NameErrors。

3 个答案: