加密字符串5

Question

def main():
# open file to be used
  inFile = open ('input.txt', 'r')
  fileContent = inFile.readline()
  choice = input('Do you want to encrypt or decrypt? (E / D): ')
# find even and odd characters in string
  if (choice == 'E'):
      for i in range(0, len(fileContent), 2):
        even_str = fileContent[i]
      print(even_str)
      for i in range(1, len(fileContent), 2):
        odd_str = fileContent[i]
      encrypted_str = odd_str + even_str
# open outfile and write new strings in
      outFile = open("output.txt", "w")
      outFile.write(even_str)
      outFile.write(odd_str)
      outFile.write(encrypted_str)
      outFile.close()
  if (choice == 'D'):
      half = fileContent // 2
      even_str = fileContent[:half]
# return this if user has incorrect input
  if (choice != 'E' and choice != 'D'):
      print ('')
      print ('Wrong input. Bye.')
      return
  inFile.close()
main()

现在我只是测试一下even_str的输出是什么。输入是“敏捷的棕色狐狸跳过懒狗”。我一直得到的even_str输出是"g“，而我应该得到的是每个偶数字符。

Answer 1

每次通过循环都会为even_str分配一个新值，因此当循环完成时，该值将是上次分配的值--在本例中是'g‘。如果您想要一个包含所有偶数字符的列表，则需要将其作为列表，并将每个字符附加到该列表中：

even_str = list()
for i in range(0, len(fileContent), 2):
    even_str.append(fileContent[i])