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Date: Sun, 9 Jun 2013 02:08:48 -0700 (PDT)
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Subject: Re: Changing filenames from Greeklish => Greek (subprocess complain)
From: =?ISO-8859-7?B?zenq/Ovh7/Igyu/98eHy?= <nikos.gr33k@gmail.com>
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Xref: csiph.com comp.lang.python:47436

=D4=E7 =CA=F5=F1=E9=E1=EA=DE, 9 =C9=EF=F5=ED=DF=EF=F5 2013 11:55:43 =F0.=EC=
. UTC+3, =EF =F7=F1=DE=F3=F4=E7=F2 Lele Gaifax =DD=E3=F1=E1=F8=E5:
> Steven D'Aprano <steve+comp.lang.python@pearwood.info> writes:
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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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> >>=20
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> >> s =3D "=ED=DF=EA=EF=F2"
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> >> utf8_bytes =3D s.encode('utf-8')
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> >> greek_bytes =3D utf_bytes.encode('iso-8869-7')
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> >>=20
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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 a=
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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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> 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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>     >>> s =3D "=ED=DF=EA=EF=F2"
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>     >>> utf8_bytes =3D s.encode('utf-8')
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>     >>> greek_bytes =3D 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 =3D "=ED=DF=EA=EF=F2"
what_are these_bytes =3D s.encode('iso-8869-7').encode(utf-8')