Question

我正在创建一个程序，对数字列表进行各种计算。

如果有人在选择pickAFile()的文件时按“取消”，如何显示错误消息？目前，当我取消它时，我收到来自for line in file行的错误消息。

错误消息是：

>"The error was:Stream closed
> I/O operation failed.
> 
> I tried to read a file, and couldn't.  Are you sure that file exists?
> If it does exist, did you specify the correct directory/folder?"

这是我的代码：

def selectFileCalculateStatistics():

  fullPathName = pickAFile()
  file = open(fullPathName, "r")

  listNumbers = readListNumbers(file)

  min = calculateMinimum(listNumbers)

  max = calculateMaximum(listNumbers)

  mean = calculateMean(listNumbers)

  standardDeviation = calculateStandardDeviation(listNumbers, mean)

  print("The minimum number for this list is: " + str(min))
  print("The maximum number for this list is: \n" + str(max))
  print("The mean number for this list is: " + str(round(mean, 2)))
  print("The standard deviation for this list is: " + str(round(standardDeviation, 2)))

  file.close()


def readListNumbers(fullPathName):

      file = open(fullPathName, "r")
      listNumbers = []

      for line in file:
        listNumbers.append(float(line.rstrip('\n')))

      return listNumbers

Answer 1

如果用户按下取消按钮，pickAFile()会返回None，您可以引发一些异常：

fullPathName = pickAFile()
if not fullPathName:
    raise IOError('Cancel pressed')

如何在Jython中使用pickAFile（）创建错误消息？

1 个答案: