Question

我修改了引文以修复语法错误。现在我收到的错误是这个：

Traceback (most recent call last):
  File "C:\Users\Alex\Desktop\Programming Concepts\Labs\Chapter 11\Lab 8.py", line 78, in <module>
    main()
  File "C:\Users\Alex\Desktop\Programming Concepts\Labs\Chapter 11\Lab 8.py", line 18, in main
    totalPints = getTotal(pints)
  File "C:\Users\Alex\Desktop\Programming Concepts\Labs\Chapter 11\Lab 8.py", line 42, in getTotal
    totalPints += pints[counter]
  UnboundLocalError: local variable 'totalPints' referenced before assignment

到目前为止，这是我的代码：

# Lab 8-3 Blood Drive

# The main function
def main():
    endProgram = 'no'
    print
    while endProgram == 'no':
        print
        # Declare variables
        pints = [0] * 7

        # Function calls
        pints = getPints(pints)
        totalPints = getTotal(pints)
        averagePints = getAverage(totalPints)
        highPints = getHigh(pints)
        lowPints = getLow(pints)
        displayInfo(averagePints, highPints, lowPints)

        endProgram = input('Do you want to end program? (Enter no or yes): ')
        while not (endProgram == 'yes' or endProgram == 'no'):
            print('Please enter a yes or no')
            endProgram = input('Do you want to end program? (Enter no or yes): ')

# The getPints function
def getPints(pints):
    counter = 0
    while counter < 7:
        numEntered = input('Enter pints collected: ')
        pints[counter] = int(numEntered)
        counter += 1
    return pints

# The getTotal function
def getTotal(pints):
    counter = 0
    while counter < 7:
        totalPints += pints[counter]
        counter += 1
    return totalPints

# The getAverage function
def getAverage(totalPints):
    averagePints = float(totalPints) / 7
    return averagePints

# The getHigh function
def getHigh(pints):
    highPints = pints[0]
    counter = 1
    while counter < 7:
        if pints[counter] > highPints:
            highPints = pints[counter]
        counter += 1
    return highPints

# The getLow function
def getLow():
    lowPints = pints[0]
    counter = 1
    while counter < 7:
        if pints[counter] < lowPints:\
           lowPints = pints[counter]
        counter += 1
    return lowPints

# The displayInfo function
def displayInfo(averagePints, highPints, lowPints):
    print('The average number of pints donated is ',averagePints)
    print('The highest pints donated is ', highPints)
    print('The lowest number of pints donated is ', lowPints)

# Calls main
main()

如果有人可以将这些代码复制并粘贴到他们的python中并帮助排除故障，我会非常感激！

Answer 1

您需要更改引号的所有‘（'或"）。您还需要在getPints函数中检查缩进：

# The getPints function
def getPints(pints):
counter = 0
while counter < 7:
    numEntered = input(‘Enter pints collected: ‘)
    pints[counter] = int(numEntered)
    counter += 1
return pints

在函数定义之后再缩进一个级别，就像在main函数中一样：

# The getPints function
def getPints(pints):
    counter = 0
    while counter < 7:
        numEntered = input(‘Enter pints collected: ‘)
        pints[counter] = int(numEntered)
        counter += 1
    return pints

Answer 2

“赋值前引用的变量”只表示您正在使用尚不存在的变量。在您的代码中，问题是这一行：

totalPints += pints[counter]

这是totalPints的第一次出现。请记住，“+ =”构造完全等同于

totalPints = totalPints + pints[counter]

这是python反对的右手事件。要解决此问题，请使用

初始化变量

totalPints = 0

进入循环之前。

Answer 3

这很容易解决。您只需在向其添加内容之前分配变量即可。

totalPins = 0

或

totalPins = ""

在进入循环之前

应该可以做到。

为什么我的代码中出现“UnboundLocalError”？

3 个答案: