the same strings, different utf-8 repr values?

[Slowness Chen]

got it. thanks.
John Machin 写道：

> slowness.chen at gmail.com wrote:
> > I have two files:
> >
> > test.py:
> > --------------------------------------------------
> > # -*- encoding : utf8 -*-
> > print 'in this file', repr('中文')
> >
> > # tt.txt is saved as utf8 encoding
> > f = file('tt.txt')
> > line1 = f.readline().strip()
> > print 'another file', repr(line1)
> > -------------------------------------------------------
> >
> > tt.txt:
> > ----------------------------------------------------
> > 中文
> > test
> > -------------------------------------------------------
> > run test.py and I get the following output:
> > in this file '\xe4\xb8\xad\xe6\x96\x87'
> > another file '\xef\xbb\xbf\xe4\xb8\xad\xe6\x96\x87'
> >
> > and I cann't encode line1 like:
> >        line1.decode('utf8').encode('gbk')
> > get this error:
> > UnicodeEncodeError: 'gbk' codec can't encode character u'\ufeff' in
> > position 0:
> > illegal multibyte sequence
> >
> > why did I get the different repr values?
>
> Because whatever you used to "save as" that file has retained or
> inserted a BOM (byte order mark, U+FEFF) at the start of the file
> before encoding as UTF-8. It's the '\xef\xbb\xbf' at the start of the
> file, and also the u'\ufeff' that is giving the gbk codec indigestion.
> You can remove it in your script.
> 
> HTH
> John