编码☺当IBM-437失败，而其他有效字符如é成功 [英] Encoding ☺ as IBM-437 fails while other valid characters like é succeed

问题描述

☺：

>>> bytes('☺','ibm437')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.3/encodings/cp437.py", line 12, in encode
    return codecs.charmap_encode(input,errors,encoding_map)
UnicodeEncodeError: 'charmap' codec can't encode character '\u263a' in position 0: character maps to <undefined>

相对于é，它有效：

>>> bytes('é','ibm437')
b'\x82'

I期待☺把我带回来 b'\x01'。如何做到这一点？

I expect ☺ to bring me back b'\x01'. How can I make this the case?

代码页面437的图像。

推荐答案

IBM-437有些特别，不仅代码页（即定义字节值128-255应该发生什么），而且还重新定义了一些ASCII控制字符，但只在某些上下文中。 Python将这些有问题的代码点映射到控制字符，而不是在某些上下文中显示的可见字符。

IBM-437 is somewhat special in that it is not only a codepage (i.e. defines what should happen for byte values 128-255), but also redefines some of the ASCII control characters, but only in some contexts. Python maps those problematic codepoints to control characters, and not to the visible characters they were displayed as in some contexts.

要转换，可以使用以下帮助器方法： / p>

To convert, you can use the following helper method:

ibm437_visible = lambda byt: byt.decode('ibm437').translate({
    0x01: "\u263A", 0x02: "\u263B", 0x03: "\u2665", 0x04: "\u2666",
    0x05: "\u2663", 0x06: "\u2660", 0x07: "\u2022", 0x08: "\u25D8",
    0x09: "\u25CB", 0x0a: "\u25D9", 0x0b: "\u2642", 0x0c: "\u2640",
    0x0d: "\u266A", 0x0e: "\u266B", 0x0f: "\u263C", 0x10: "\u25BA",
    0x11: "\u25C4", 0x12: "\u2195", 0x13: "\u203C", 0x14: "\u00B6",
    0x15: "\u00A7", 0x16: "\u25AC", 0x17: "\u21A8", 0x18: "\u2191", 
    0x19: "\u2193", 0x1a: "\u2192", 0x1b: "\u2190", 0x1c: "\u221F",
    0x1d: "\u2194", 0x1e: "\u25B2", 0x1f: "\u25BC", 0x7f: "\u2302",
})
assert ibm437_visible(b'\x01') == '☺'

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