how to fix ValueError: list index out of range

Question

我不断收到此错误：

第 23 行，在编码中 raw_out[i][pos] = 消息[pos] IndexError: 列表索引超出范围

这部分节目：

def encode(message: str, key: int) -> str:
"""
Encode text using Rail-fence Cipher.

Replace all spaces with '_'.

:param message: Text to be encoded.
:param key: Encryption key.
:return: Decoded string.
"""
message = message.replace(" ", "_")

down = True
raw_out = []
out = ''
i = 0
for x in range(key):
    raw_out.append({})
for pos in range(len(message)):
    raw_out[i][pos] = message[pos]
    if i == key - 1:
        down = False
    if i == 0:
        down = True
    if down:
        i = i + 1
    else:
        i = i - 1
for p in raw_out:
    for q in p:
        out += p[q]
return out

我不确定如何修复错误。有什么想法吗？

Answer 1

当键为一或当键大于字符串的长度时 return 字符串原样。做任何处理都没有意义。

在行

之后

message = message.replace(" ", "_")

你可以检查条件

if key == 1 or key > len(message):
    return message

how to fix ValueError: list index out of range

how to fix ValueError: list index out of range

python-3.x

pycharm

index-error