Τη Κυριακή, 9 Ιουνίου 2013 11:55:43 π.μ. UTC+3, ο χρήστης Lele Gaifax έγραψε:
> Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> writes:
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>
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> > On Sat, 08 Jun 2013 22:09:57 -0700, nagia.retsina wrote:
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> >
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> >> chr('A') would give me the mapping of this char, the number 65 while
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> >> ord(65) would output the char 'A' likewise.
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> >
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> > Correct. Python uses Unicode, where code-point 65 ("ordinal value 65")
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> > means letter "A".
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> Actually, that's the other way around:
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> >>> chr(65)
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> 'A'
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> >>> ord('A')
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> 65
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>
>
> >> What would happen if we we try to re-encode bytes on the disk? like
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> >> trying:
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> >>
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> >> s = "νίκος"
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> >> utf8_bytes = s.encode('utf-8')
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> >> greek_bytes = utf_bytes.encode('iso-8869-7')
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> >>
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> >> Can we re-encode twice or as many times we want and then decode back
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> >> respectively lke?
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> >
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> > Of course. Bytes have no memory of where they came from, or what they are
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> > used for. All you are doing is flipping bits on a memory chip, or on a
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> > hard drive. So long as *you* remember which encoding is the right one,
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> > there is no problem. If you forget, and start using the wrong one, you
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> > will get garbage characters, mojibake, or errors.
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>
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> Uhm, no: "encode" transforms a Unicode string into an array of bytes,
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> "decode" does the opposite transformation. You cannot do the former on
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> an "arbitrary" array of bytes:
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>
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> >>> s = "νίκος"
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> >>> utf8_bytes = s.encode('utf-8')
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> >>> greek_bytes = utf8_bytes.encode('iso-8869-7')
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> Traceback (most recent call last):
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> File "<stdin>", line 1, in <module>
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> AttributeError: 'bytes' object has no attribute 'encode'
So something encoded into bytes cannot be re-encoded to some other bytes.
How about a string i wonder?
s = "νίκος"
what_are these_bytes = s.encode('iso-8869-7').encode(utf-8')
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