我希望这很容易解决 . 我使用Python在Windows Powershell中获得的错误如下：

Traceback (most recent call last): File "[filename.py]", line 66, in main(ciphertext) NameError: name 'ciphertext' is not defined

我的代码：

def main():

# cipherOne contains encrypted Cesear cipher

myMessage = cipherOne

ciphertext = encryptMessage(key, myMessage)

# Print the encrypted string in ciphertext to the screen, with

# a | (called "pipe" character) after it in case there are spaces at

# the end of the encrypted message.

print(ciphertext)

def encryptMessage(key, message):

# Each string in ciphertext represents a column in the grid.

ciphertext = [''] * key

# Loop through each column in ciphertext.

for col in range(key):

pointer = col

# Keep looping until pointer goes past the length of the message.

while pointer < len(message):

# Place the character at pointer in message at the end of the

# current column in the ciphertext list.

ciphertext[col] += message[pointer]

# move pointer over

pointer += key

# Convert the ciphertext list into a single string value and return it.

return ''.join(ciphertext)

# call main() function.

if __name__ == '__main__':

main()

target = open (filenamenew, 'a')

target.write(ciphertext) #the error

target.close()

我可以将密文中的加密字符串打印到屏幕上，没有任何问题，但无法解决如何通过此错误，我可以将密文附加到.txt文件 .