声明为全局的变量不能在另一个函数中调用

Question

在takeUnit1函数中，我尝试在TOtbsp函数中访问convFROMconv变量。当我试着运行它时，我得到：

Traceback (most recent call last):
   File "hb.py", line 124, in <module>
       takeUnit()
   File "hb.py", line 28, in takeUnit1
       takeUnit2()
   File "hb.py", line 82, in takeUnit2
       TOtbsp()
NameError: name 'convFROMconv' is not defined

我尝试在convFROMconv的每个案例的声明之前添加一个全局声明，如下所示：

    if convFROM == '1':
        global convFROMconv
        convFROMconv = 'Tablespoons'

    elif convFROM == '2':
        global convFROMconv
        convFROMconv = 'Teaspoons'

    elif convFROM == '3':
        global convFROMconv
        convFROMconv = 'Cups'

    elif convFROM == '4':
        global convFROMconv
        convFROMconv = 'Quarts'

我不确定是否有什么小规则和我要做的事有关。有可能吗

import os

tbsp = {'cup' : 0.0625 , 'tsp' : 3 , 'quart' : 0.015625 , 'floz' : 0.5 , 'pint' : 0.03125 , 'gal' : 0.00390625 , 'ml' : 14.7868 , 'liter' : 0.0147868}
tsp = {'cup' : 0.0208333 , 'tbsp' : 0.333333 , 'quart' : 0.0052083333 , 'floz' : 0.1666666667 , 'pint' :  0.0104166667, 'gal' : 0.0013020833 , 'ml' : 4.92892 , 'liter' : 0.00492892}
cup = {'tbsp' : 16 , 'tsp' : 48 , 'quart' : 0.25 , 'floz' : 8.32674 , 'pint' : 0.5 , 'gal' : 0.0625 , 'ml' : 236.588 , 'liter' : 0.236588}
quart = {'cup' : 4 , 'tsp' : 192 , 'tbsp' : 64 , 'floz' : 32 , 'pint' : 2 , 'gal' : 0.25 , 'ml' : 946.353 , 'liter' : 0.946353}
floz = {'cup' : 0.125 , 'tsp' : 6 , 'quart' : 0.03125 , 'tbsp' : 2 , 'pint' : 0.0625 , 'gal' : 0.0078125 , 'ml' : 29.5735 , 'liter' : 0.0295735}
pint = {'cup' : 2 , 'tsp' : 96 , 'quart' : 0.5 , 'floz' : 16 , 'tbsp' : 32 , 'gal' : 0.125 , 'ml' : 473.176 , 'liter' : 0.473176}
gal = {'cup' : 16 , 'tsp' : 768 , 'quart' : 4 , 'floz' : 128 , 'pint' : 8 , 'tbsp' : 256 , 'ml' : 3785.41 , 'liter' : 3.78541}
ml = {'cup' : 0.0042267571 , 'tsp' : 0.202884 , 'quart' : 0.00105669 , 'floz' : 0.033814 , 'pint' : 0.00211338 , 'gal' : 0.000264172 , 'tbsp' : 0.067628 , 'liter' : 0.001}
liter = {'cup' : 4.226757063 , 'tsp' : 202.884 , 'quart' : 1.05669 , 'floz' : 33.814 , 'pint' : 2.11338 , 'gal' : 0.264172 , 'ml' : 1000 , 'tbsp' : 67.628}
acceptableInputs = ['1', '2', '3', '4', '5', '6', '7', '8']

def takeUnit1 ():
    print ('Unit Converter')
    print ('Select the unit you want to convert FROM')
    print ('1 Tbsp - Tablespoon')
    print ('2 Tsp - Teaspoon')
    print ('3 C - Cups')
    print ('4 qt. - Quart')
    print ('5 fl. oz. - Fluid Ounce')
    print ('6 gal. - Gallon')
    print ('7 ml - Milliliter')
    print ('8 L - Liter')
    convFROM = input('Unit: ')

    if convFROM in acceptableInputs:
        takeUnit2()
        global convFROMconv
        if convFROM == '1':
            convFROMconv = 'Tablespoons'

        elif convFROM == '2':
            convFROMconv = 'Teaspoons'

        elif convFROM == '3':
            convFROMconv = 'Cups'

        elif convFROM == '4':
            convFROMconv = 'Quarts'

        elif convFROM == '5':
            convFROMconv = 'Fluid Ounces'

        elif convFROM == '6':
            convFROMconv = 'Gallons'

        elif convFROM == '7':
            convFROMconv = 'Milliliters'

        elif convFROM == '8':
            convFROMconv = 'Liters'

        else:
            print ('')

    else:
        print('That is not an acceptable input, please try again')


def takeUnit2 ():
    os.system('cls')
    print ('Select the unit you want to convert TO')
    print ('1 Tbsp - Tablespoon')
    print ('2 Tsp - Teaspoon')
    print ('3 C - Cups')
    print ('4 qt. - Quart')
    print ('5 fl. oz. - Fluid Ounce')
    print ('6 gal. - Gallon')
    print ('7 ml - Milliliter')
    print ('8 L - Liter')
    convTO = input('Unit: ')

    if convTO in acceptableInputs:
        print('yay')

        global convTOname #Making convTOconv global
        global TOfunc1
        if convTO == '1': #This whole statement converts the input number to its corresponding name
            convTOname = 'Tablespoons'
            TOfunc1 = 'TOtbsp'
            TOtbsp()

        elif convTO == '2':
            convTOname = 'Teaspoons'
            TOfunc1 = 'TOtsp'

        elif convTO == '3':
            convTOname = 'Cups'
            TOfunc1 = 'TOcups'

        elif convTO == '4':
            convTOname = 'Quarts'
            TOfunc1 = 'TOquarts'

        elif convTO == '5':
            convTOname = 'Fluid Ounces'
            TOfunc1 = 'TOfloz'

        elif convTO == '6':
            convTOname = 'Gallons'
            TOfunc1 = 'TOgal'

        elif convTO == '7':
            convTOname = 'Milliliters'
            TOfunc1 = 'TOml'

        elif convTO == '8':
            convTOname = 'Liters'
            TOfunc1 = 'TOliters'


        else:
            print ('')

    else:
        print('That is not an acceptable input, please try again')






takeUnit1()

def TOtbsp ():
    os.system('cls')
    print ('Convert tablespoons to: ' + convFROMconv)
    print ('YAY')

谢谢你的帮助

Answer 1

变量不是问题所在。 您的错误是由于函数TOtbsp而发生的

Python是一种脚本语言。 所以，在使用之前应该先定义一个函数

将TOtbsp移到源代码的顶部