unpack_from 需要至少 1164 字节的缓冲区 [关闭]

我正在使用 struct 来解析固定宽度字符串。但是，我在处理大于 1000 字节的固定宽度字符串时遇到了一些麻烦。

例如，当我执行以下代码时：

import struct
fmt = '2s25s16s1s40s2s1s1s2s9s1s6s10s25s2s2s9s8s2s2s4x8s2x2s2s2s2s2s1x13s6s2s2s2s2s1x3s4s6s4s12x1s2s1x7s1s2s2s2s2s2s1x3s6x2s2x2s2x2s2x2s2x2s2x2s6s2x1s4x4s2s2s2s2s2s2s2s8x3s3s3s3s3s3s3s3s3s2s2s2s2s2s2s8s2x2s2s2s2s2s150s50s4x1s2s8s15x30s30s10s15s15s10s10s10s10s12s3s3s3s3s1s3s3s1x15s2s3s8s2s2s2s2s2s16s2s3s2x2s3s2x1s1s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s10x2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s42s6s21s3s3s3s3s3s3s3s3s3s3s3s3s7s'
parse = struct.Struct(fmt).unpack_from

line = '1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ123456'
parse(line.encode())

我收到以下错误：

Traceback (most recent call last):
  File "so.py", line 6, in <module>
    parse(line.encode())
struct.error: unpack_from requires a buffer of at least 1164 bytes

我一直在寻找将缓冲区设置为 1164 字节的方法，但没有成功。

我们来看看https://docs.python.org/3.0/library/struct.html#struct.unpack_from https://docs.python.org/3.0/library/struct.html#struct.unpack_from首先，它说：

根据给定的格式解压缓冲区。结果是 元组，即使它只包含一项。缓冲区必须包含 格式所需的最少数据量 (len(buffer[offset:]) 必须至少为 calcsize(fmt))。

让我们先在你的 fmt 上尝试 calcsize，print(struct.calcsize(fmt))1164 说。

现在让我们看看缓冲区的长度len(line)，它说 1050。

所以错误是因为您没有遵循文档提供的指南......

PS: parse((line+line[0:struct.calcsize(fmt)-len(line)]).encode())