Question

我是python的新手，这是我最近收到的代码，它一直工作到第29行。这是发生错误的地方：

Traceback (most recent call last):
  File "N:/computing/11woojos_A453/A453_ASSIGNMENT/Task two/task 2 SO.py", line 30, in <module>
    print (keyword_encrypt)(shift_key, phrase)
TypeError: 'NoneType' object is not callable

我的代码：

#!/usr/bin/env python2
from itertools import islice, cycle

phrase = input('message you would like to encrypt: ')
shift_key = input('shift key: ')

def keyword_encrypt(key, phrase): # e.g. "ba","abcde"
    # make phrase and key into arrays of letters (equal length)
    phrase = [ letter for letter in phrase.lower()]     # e.g. ['a', 'b', 'c', 'd', 'e'] 
    key = list(islice(cycle(key.lower()), len(phrase))) # e.g. ['b', 'a', 'b', 'a', 'b']
    encrypted = []

    for i in range(len(phrase)):
        k_letter = (ord(key[i]) - ord('a'))
        p_letter = (ord(phrase[i]) - ord('a'))

        new_letter =  p_letter + k_letter

        if new_letter >= 26:
            new_letter -= 26

        new_letter = chr(new_letter + ord('a'))
        encrypted.append(new_letter)

    # make the list a string again with the join command
    return "".join(encrypted)

print ('encrypted message:')
print ('_')
print (keyword_encrypt)(shift_key, phrase)

Answer 1

代码正在尝试调用print()函数的结果：

result = print (keyword_encrypt)
result(shift_key, phrase)

这不会奏效，因为print()总是会返回None。

您可能打算调用keyword_encrypt()函数并打印该调用的返回值：

print(keyword_encrypt(shift_key, phrase))

代码写得有点奇怪，括号和空格，但是如果你实际上用Python 2运行它（作为文件的第一行#!尝试做），那么发布的代码实际上是工作。这是因为print是Python 2中的一个语句，keyword_encrypt周围的括号实际上被忽略了。

对象不可调用。错误Python

1 个答案: