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I'm having some brain failure in understanding reading and writing text to a file (Python 2.4).
# The string, which has an a-acute in it.
ss = u'Capit\xe1n'
ss8 = ss.encode('utf8')
repr(ss), repr(ss8)
("u'Capit\xe1n'", "'Capit\xc3\xa1n'")
print ss, ss8
print >> open('f1','w'), ss8
>>> file('f1').read()
'Capit\xc3\xa1n\n'
So I type in Capit\xc3\xa1n into my favorite editor, in file f2.
Then:
>>> open('f1').read()
'Capit\xc3\xa1n\n'
>>> open('f2').read()
'Capit\\xc3\\xa1n\n'
>>> open('f1').read().decode('utf8')
u'Capit\xe1n\n'
>>> open('f2').read().decode('utf8')
u'Capit\\xc3\\xa1n\n'
What am I not understanding here? Clearly there is some vital bit of magic (or good sense) that I'm missing. What does one type into text files to get proper conversions?
What I'm truly failing to grok here, is what the point of the UTF-8 representation is, if you can't actually get Python to recognize it, when it comes from outside. Maybe I should just JSON dump the string, and use that instead, since that has an asciiable representation! More to the point, is there an ASCII representation of this Unicode object that Python will recognize and decode, when coming in from a file? If so, how do I get it?
>>> print simplejson.dumps(ss)
'"Capit\u00e1n"'
>>> print >> file('f3','w'), simplejson.dumps(ss)
>>> simplejson.load(open('f3'))
u'Capit\xe1n'
Rather than mess with .encode and .decode, specify the encoding when opening the file. The io module, added in Python 2.6, provides an io.open function, which allows specifying the file's encoding.
Supposing the file is encoded in UTF-8, we can use:
>>> import io
>>> f = io.open("test", mode="r", encoding="utf-8")
Then f.read returns a decoded Unicode object:
>>> f.read()
u'Capit\xe1l\n\n'
In 3.x, the io.open function is an alias for the built-in open function, which supports the encoding argument (it does not in 2.x).
We can also use open from the codecs standard library module:
>>> import codecs
>>> f = codecs.open("test", "r", "utf-8")
>>> f.read()
u'Capit\xe1l\n\n'
Note, however, that this can cause problems when mixing read() and readline().
In the notation u'Capit\xe1n\n' (should be just 'Capit\xe1n\n' in 3.x, and must be in 3.0 and 3.1), the \xe1 represents just one character. \x is an escape sequence, indicating that e1 is in hexadecimal.
Writing Capit\xc3\xa1n into the file in a text editor means that it actually contains \xc3\xa1. Those are 8 bytes and the code reads them all. We can see this by displaying the result:
# Python 3.x - reading the file as bytes rather than text,
# to ensure we see the raw data
>>> open('f2', 'rb').read()
b'Capit\\xc3\\xa1n\n'
# Python 2.x
>>> open('f2').read()
'Capit\\xc3\\xa1n\n'
Instead, just input characters like á in the editor, which should then handle the conversion to UTF-8 and save it.
In 2.x, a string that actually contains these backslash-escape sequences can be decoded using the string_escape codec:
# Python 2.x
>>> print 'Capit\\xc3\\xa1n\n'.decode('string_escape')
Capitán
The result is a str that is encoded in UTF-8 where the accented character is represented by the two bytes that were written \\xc3\\xa1 in the original string. To get a unicode result, decode again with UTF-8.
In 3.x, the string_escape codec is replaced with unicode_escape, and it is strictly enforced that we can only encode from a str to bytes, and decode from bytes to str. unicode_escape needs to start with a bytes in order to process the escape sequences (the other way around, it adds them); and then it will treat the resulting \xc3 and \xa1 as character escapes rather than byte escapes. As a result, we have to do a bit more work:
# Python 3.x
>>> 'Capit\\xc3\\xa1n\n'.encode('ascii').decode('unicode_escape').encode('latin-1').decode('utf-8')
'Capitán\n'
Now all you need in Python3 is open(Filename, 'r', encoding='utf-8')
[Edit on 2016-02-10 for requested clarification]
Python3 added the encoding parameter to its open function. The following information about the open function is gathered from here: https://docs.python.org/3/library/functions.html#open
open(file, mode='r', buffering=-1,
encoding=None, errors=None, newline=None,
closefd=True, opener=None)
Encoding is the name of the encoding used to decode or encode the
file. This should only be used in text mode. The default encoding is
platform dependent (whatever locale.getpreferredencoding()
returns), but any text encoding supported by Python can be used.
See the codecs module for the list of supported encodings.
So by adding encoding='utf-8' as a parameter to the open function, the file reading and writing is all done as utf8 (which is also now the default encoding of everything done in Python.)
So, I've found a solution for what I'm looking for, which is:
print open('f2').read().decode('string-escape').decode("utf-8")
There are some unusual codecs that are useful here. This particular reading allows one to take UTF-8 representations from within Python, copy them into an ASCII file, and have them be read in to Unicode. Under the "string-escape" decode, the slashes won't be doubled.
This allows for the sort of round trip that I was imagining.
This works for reading a file with UTF-8 encoding in Python 3.2:
import codecs
f = codecs.open('file_name.txt', 'r', 'UTF-8')
for line in f:
print(line)
# -*- encoding: utf-8 -*-
# converting a unknown formatting file in utf-8
import codecs
import commands
file_location = "jumper.sub"
file_encoding = commands.getoutput('file -b --mime-encoding %s' % file_location)
file_stream = codecs.open(file_location, 'r', file_encoding)
file_output = codecs.open(file_location+"b", 'w', 'utf-8')
for l in file_stream:
file_output.write(l)
file_stream.close()
file_output.close()
Aside from codecs.open(), io.open() can be used in both 2.x and 3.x to read and write text files. Example:
import io
text = u'á'
encoding = 'utf8'
with io.open('data.txt', 'w', encoding=encoding, newline='\n') as fout:
fout.write(text)
with io.open('data.txt', 'r', encoding=encoding, newline='\n') as fin:
text2 = fin.read()
assert text == text2
To read in an Unicode string and then send to HTML, I did this:
fileline.decode("utf-8").encode('ascii', 'xmlcharrefreplace')
Useful for python powered http servers.
Well, your favorite text editor does not realize that \xc3\xa1 are supposed to be character literals, but it interprets them as text. That's why you get the double backslashes in the last line -- it's now a real backslash + xc3, etc. in your file.
If you want to read and write encoded files in Python, best use the codecs module.
Pasting text between the terminal and applications is difficult, because you don't know which program will interpret your text using which encoding. You could try the following:
>>> s = file("f1").read()
>>> print unicode(s, "Latin-1")
Capitán
Then paste this string into your editor and make sure that it stores it using Latin-1. Under the assumption that the clipboard does not garble the string, the round trip should work.
You have stumbled over the general problem with encodings: How can I tell in which encoding a file is?
Answer: You can't unless the file format provides for this. XML, for example, begins with:
<?xml encoding="utf-8"?>
This header was carefully chosen so that it can be read no matter the encoding. In your case, there is no such hint, hence neither your editor nor Python has any idea what is going on. Therefore, you must use the codecs module and use codecs.open(path,mode,encoding) which provides the missing bit in Python.
As for your editor, you must check if it offers some way to set the encoding of a file.
The point of UTF-8 is to be able to encode 21-bit characters (Unicode) as an 8-bit data stream (because that's the only thing all computers in the world can handle). But since most OSs predate the Unicode era, they don't have suitable tools to attach the encoding information to files on the hard disk.
The next issue is the representation in Python. This is explained perfectly in the comment by heikogerlach. You must understand that your console can only display ASCII. In order to display Unicode or anything >= charcode 128, it must use some means of escaping. In your editor, you must not type the escaped display string but what the string means (in this case, you must enter the umlaut and save the file).
That said, you can use the Python function eval() to turn an escaped string into a string:
>>> x = eval("'Capit\\xc3\\xa1n\\n'")
>>> x
'Capit\xc3\xa1n\n'
>>> x[5]
'\xc3'
>>> len(x[5])
1
As you can see, the string "\xc3" has been turned into a single character. This is now an 8-bit string, UTF-8 encoded. To get Unicode:
>>> x.decode('utf-8')
u'Capit\xe1n\n'
Gregg Lind asked: I think there are some pieces missing here: the file f2 contains: hex:
0000000: 4361 7069 745c 7863 335c 7861 316e Capit\xc3\xa1n
codecs.open('f2','rb', 'utf-8'), for example, reads them all in a separate chars (expected) Is there any way to write to a file in ASCII that would work?
Answer: That depends on what you mean. ASCII can't represent characters > 127. So you need some way to say "the next few characters mean something special" which is what the sequence "\x" does. It says: The next two characters are the code of a single character. "\u" does the same using four characters to encode Unicode up to 0xFFFF (65535).
So you can't directly write Unicode to ASCII (because ASCII simply doesn't contain the same characters). You can write it as string escapes (as in f2); in this case, the file can be represented as ASCII. Or you can write it as UTF-8, in which case, you need an 8-bit safe stream.
Your solution using decode('string-escape') does work, but you must be aware how much memory you use: Three times the amount of using codecs.open().
Remember that a file is just a sequence of bytes with 8 bits. Neither the bits nor the bytes have a meaning. It's you who says "65 means 'A'". Since \xc3\xa1 should become "à" but the computer has no means to know, you must tell it by specifying the encoding which was used when writing the file.
The \x.. sequence is something that's specific to Python. It's not a universal byte escape sequence.
How you actually enter in UTF-8-encoded non-ASCII depends on your OS and/or your editor. Here's how you do it in Windows. For OS X to enter a with an acute accent you can just hit option + E, then A, and almost all text editors in OS X support UTF-8.
You can also improve the original open() function to work with Unicode files by replacing it in place, using the partial function. The beauty of this solution is you don't need to change any old code. It's transparent.
import codecs
import functools
open = functools.partial(codecs.open, encoding='utf-8')
I was trying to parse iCal using Python 2.7.9:
from icalendar import Calendar
But I was getting:
Traceback (most recent call last):
File "ical.py", line 92, in parse
print "{}".format(e[attr])
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe1' in position 7: ordinal not in range(128)
and it was fixed with just:
print "{}".format(e[attr].encode("utf-8"))
(Now it can print liké á böss.)
I found the most simple approach by changing the default encoding of the whole script to be 'UTF-8':
import sys
reload(sys)
sys.setdefaultencoding('utf8')
any open, print or other statement will just use utf8.
Works at least for Python 2.7.9.
Thx goes to https://markhneedham.com/blog/2015/05/21/python-unicodeencodeerror-ascii-codec-cant-encode-character-uxfc-in-position-11-ordinal-not-in-range128/ (look at the end).
I am on Mac OS X 10.8.2
When I try to find files with filenames that contain non-ASCII-characters I get no results although I know for sure that they are existing. Take for example the console input
> find */Bärlauch*
I get no results. But if I try without the umlaut I get
> find */B*rlauch*
images/Bärlauch1.JPG
So the file is definitely existing. If I rename the file replacing 'ä' by 'ae' the file is being found.
Similarily the Python module glob is not able to find the file:
>>> glob.glob('*/B*rlauch*')
['images/Bärlauch1.JPG']
>>> glob.glob('*/Bärlauch*')
[]
I figured out it must have something to do with the encoding but my terminal is set to be utf-8 and I am using Python 3.3.0 which uses unicode strings.
Mac OS X uses denormalized characters always for filenames on HFS+. Use unicodedata.normalize('NFD', pattern) to denormalize the glob pattern.
import unicodedata
glob.glob(unicodedata.normalize('NFD', '*/Bärlauch*'))
Python programs are fundamentally text files. Conventionally, people write them using only characters from the ASCII character set, and thus do not have to think about the encoding they write them in: all character sets agree on how ASCII characters should be decoded.
You have written a Python program using a non-ASCII character. Your program thus comes with an implicit encoding (which you haven't mentioned): to save such a file, you have to decide how you are going to represent a-umlaut on disk. I would guess that perhaps your editor has chosen something non-Unicode for you.
Anyway, there are two ways around such a problem: either you can restrict yourself to using only ASCII characters in the source code of your program, or you can declare to Python that you want it to read the text file with a specific encoding.
To do the former, you should replace the a-umlaut with its Unicode escape sequence (which I think is \x0228 but can't test at the moment). To do the latter, you should add a coding declaration at the top of the file:
# -*- coding: <your encoding> -*-
I wrote a simple file parser and writer, but then I came across an article talking about the importance of unicode and then it occurred to me that I'm assuming the input file is ascii encoded, which may not be the case all the time, though it would be rare in my situation.
In those rare cases, I would expect UTF-8 encoded files.
Is there a way to work with UTF-8 files by simply changing how I read and write? All I do with the strings is store them and then write them out, so I just need to make sure I can read them, store them, and write them properly.
Furthermore, would I have to treat ascii and UTF-8 files separately and write different functions for each? I have not worked with anything other than ascii files yet and only read about handling unicode.
Python natively supports Unicode. If you directly read and write from the first file to the second, then no data is lost as it copies the bytes verbatim. However, if you decode the string and then re-encode it, you'll need to make sure you use the right encoding.
If you are using Python 2, you can simply change all your str objects to unicode objects. Unicode objects have all the same methods as strings but are encoded in a unicode format instead of ASCII. See http://docs.python.org/library/functions.html#unicode .
If you are using Python 3, strings are encoded in UTF-8 by default.
If you are using Python 2.6 or later, you can use the io library and its io.open method to open the files you want. It has an encoding argument which should be set to 'utf-8' in your case. When you read or write the returned file objects, string are automatically en-/decoded.
Anyway, you don't need to do something special for ASCII, because UTF-8 is a superset of ASCII.
So long as you are only reading and writing to files and not expecting any other type of encoded input, then you should not have to do anything special.
% cat /tmp/u
π is 3.14.
% file /tmp/u
/tmp/u: UTF-8 Unicode text
% cat f.py
f = open('/tmp/u', 'r')
d = f.read()
print d.split()
f.close()
% python f.py
['\xcf\x80', 'is', '3.14.']
This changes when you declare or accept standard input using UTF-8.
% cat g.py
s = 'π is 3.14.'
print s.split()
% python g.py
File "g.py", line 1
SyntaxError: Non-ASCII character '\xcf' in file g.py on line 1, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details
To handle this properly, declare the encoding for the Python program at the beginning per PEP 263 (referenced by the SyntaxError exception above).
% cat h.py
# -*- coding: utf-8 -*-
s = 'π is 3.14.'
print s.split()
% python h.py
['\xcf\x80', 'is', '3.14.']
I have a file with the following path : D:/bar/クレイジー・ヒッツ！/foo.abc
I am parsing the path from a XML file and storing it in a variable called path in the form of file://localhost/D:/bar/クレイジー・ヒッツ！/foo.abc
Then, the following operations are being done:
path=path.strip()
path=path[17:] #to remove the file://localhost/ part
path=urllib.url2pathname(path)
path=urllib.unquote(path)
The error is:
IOError: [Errno 2] No such file or directory: 'D:\\bar\\\xe3\x82\xaf\xe3\x83\xac\xe3\x82\xa4\xe3\x82\xb8\xe3\x83\xbc\xe3\x83\xbb\xe3\x83\x92\xe3\x83\x83\xe3\x83\x84\xef\xbc\x81\\foo.abc'
I am using Python 2.7 on Windows 7
The path in your error is:
'\xe3\x82\xaf\xe3\x83\xac\xe3\x82\xa4\xe3\x82\xb8\xe3\x83\xbc\xe3\x83\xbb\xe3\x83\x92\xe3\x83\x83\xe3\x83\x84\xef\xbc\x81'
I think this is the UTF8 encoded version of your filename.
I've created a folder of the same name on Windows7 and placed a file called 'abc.txt' in it:
>>> a = '\xe3\x82\xaf\xe3\x83\xac\xe3\x82\xa4\xe3\x82\xb8\xe3\x83\xbc\xe3\x83\xbb\xe3\x83\x92\xe3\x83\x83\xe3\x83\x84\xef\xbc\x81'
>>> os.listdir('.')
['?????\xb7???!']
>>> os.listdir(u'.') # Pass unicode to have unicode returned to you
[u'\u30af\u30ec\u30a4\u30b8\u30fc\u30fb\u30d2\u30c3\u30c4\uff01']
>>>
>>> a.decode('utf8') # UTF8 decoding your string matches the listdir output
u'\u30af\u30ec\u30a4\u30b8\u30fc\u30fb\u30d2\u30c3\u30c4\uff01'
>>> os.listdir(a.decode('utf8'))
[u'abc.txt']
So it seems that Duncan's suggestion of path.decode('utf8') does the trick.
Update
I can't test this for you, but I suggest that you try checking whether the path contains non-ascii before doing the .decode('utf8'). This is a bit hacky...
ASCII_TRANS = '_'*32 + ''.join([chr(x) for x in range(32,126)]) + '_'*130
path=path.strip()
path=path[17:] #to remove the file://localhost/ part
path=urllib.unquote(path)
if path.translate(ASCII_TRANS) != path: # Contains non-ascii
path = path.decode('utf8')
path=urllib.url2pathname(path)
Provide the filename as a unicode string to the open call.
How do you produce the filename?
if provided as a constant by you
Add a line near the beginning of your script:
# -*- coding: utf8 -*-
Then, in a UTF-8 capable editor, set path to the unicode filename:
path = u"D:/bar/クレイジー・ヒッツ！/foo.abc"
read from a list of directory contents
Retrieve the contents of the directory using a unicode dirspec:
dir_files= os.listdir(u'.')
read from a text file
Open the filename-containing-file using codecs.open to read unicode data from it. You need to specify the encoding of the file (because you know what is the “default windows charset” for non-Unicode applications on your computer).
in any case
Do a:
path= path.decode("utf8")
before opening the file; substitute the correct encoding if not "utf8".
Here's some interesting stuff from the documentation:
sys.getfilesystemencoding()
Return the name of the encoding used
to convert Unicode filenames into
system file names, or None if the
system default encoding is used. The
result value depends on the operating
system: On Mac OS X, the encoding is
'utf-8'. On Unix, the encoding is the
user’s preference according to the
result of nl_langinfo(CODESET), or
None if the nl_langinfo(CODESET)
failed. On Windows NT+, file names are
Unicode natively, so no conversion is
performed. getfilesystemencoding()
still returns 'mbcs', as this is the
encoding that applications should use
when they explicitly want to convert
Unicode strings to byte strings that
are equivalent when used as file
names. On Windows 9x, the encoding is
'mbcs'.
New in version 2.3.
If I understand this correctly, you should pass the file name as unicode:
f = open(unicode(path, encoding))
I'm having some brain failure in understanding reading and writing text to a file (Python 2.4).
# The string, which has an a-acute in it.
ss = u'Capit\xe1n'
ss8 = ss.encode('utf8')
repr(ss), repr(ss8)
("u'Capit\xe1n'", "'Capit\xc3\xa1n'")
print ss, ss8
print >> open('f1','w'), ss8
>>> file('f1').read()
'Capit\xc3\xa1n\n'
So I type in Capit\xc3\xa1n into my favorite editor, in file f2.
Then:
>>> open('f1').read()
'Capit\xc3\xa1n\n'
>>> open('f2').read()
'Capit\\xc3\\xa1n\n'
>>> open('f1').read().decode('utf8')
u'Capit\xe1n\n'
>>> open('f2').read().decode('utf8')
u'Capit\\xc3\\xa1n\n'
What am I not understanding here? Clearly there is some vital bit of magic (or good sense) that I'm missing. What does one type into text files to get proper conversions?
What I'm truly failing to grok here, is what the point of the UTF-8 representation is, if you can't actually get Python to recognize it, when it comes from outside. Maybe I should just JSON dump the string, and use that instead, since that has an asciiable representation! More to the point, is there an ASCII representation of this Unicode object that Python will recognize and decode, when coming in from a file? If so, how do I get it?
>>> print simplejson.dumps(ss)
'"Capit\u00e1n"'
>>> print >> file('f3','w'), simplejson.dumps(ss)
>>> simplejson.load(open('f3'))
u'Capit\xe1n'
Rather than mess with .encode and .decode, specify the encoding when opening the file. The io module, added in Python 2.6, provides an io.open function, which allows specifying the file's encoding.
Supposing the file is encoded in UTF-8, we can use:
>>> import io
>>> f = io.open("test", mode="r", encoding="utf-8")
Then f.read returns a decoded Unicode object:
>>> f.read()
u'Capit\xe1l\n\n'
In 3.x, the io.open function is an alias for the built-in open function, which supports the encoding argument (it does not in 2.x).
We can also use open from the codecs standard library module:
>>> import codecs
>>> f = codecs.open("test", "r", "utf-8")
>>> f.read()
u'Capit\xe1l\n\n'
Note, however, that this can cause problems when mixing read() and readline().
In the notation u'Capit\xe1n\n' (should be just 'Capit\xe1n\n' in 3.x, and must be in 3.0 and 3.1), the \xe1 represents just one character. \x is an escape sequence, indicating that e1 is in hexadecimal.
Writing Capit\xc3\xa1n into the file in a text editor means that it actually contains \xc3\xa1. Those are 8 bytes and the code reads them all. We can see this by displaying the result:
# Python 3.x - reading the file as bytes rather than text,
# to ensure we see the raw data
>>> open('f2', 'rb').read()
b'Capit\\xc3\\xa1n\n'
# Python 2.x
>>> open('f2').read()
'Capit\\xc3\\xa1n\n'
Instead, just input characters like á in the editor, which should then handle the conversion to UTF-8 and save it.
In 2.x, a string that actually contains these backslash-escape sequences can be decoded using the string_escape codec:
# Python 2.x
>>> print 'Capit\\xc3\\xa1n\n'.decode('string_escape')
Capitán
The result is a str that is encoded in UTF-8 where the accented character is represented by the two bytes that were written \\xc3\\xa1 in the original string. To get a unicode result, decode again with UTF-8.
In 3.x, the string_escape codec is replaced with unicode_escape, and it is strictly enforced that we can only encode from a str to bytes, and decode from bytes to str. unicode_escape needs to start with a bytes in order to process the escape sequences (the other way around, it adds them); and then it will treat the resulting \xc3 and \xa1 as character escapes rather than byte escapes. As a result, we have to do a bit more work:
# Python 3.x
>>> 'Capit\\xc3\\xa1n\n'.encode('ascii').decode('unicode_escape').encode('latin-1').decode('utf-8')
'Capitán\n'
Now all you need in Python3 is open(Filename, 'r', encoding='utf-8')
[Edit on 2016-02-10 for requested clarification]
Python3 added the encoding parameter to its open function. The following information about the open function is gathered from here: https://docs.python.org/3/library/functions.html#open
open(file, mode='r', buffering=-1,
encoding=None, errors=None, newline=None,
closefd=True, opener=None)
Encoding is the name of the encoding used to decode or encode the
file. This should only be used in text mode. The default encoding is
platform dependent (whatever locale.getpreferredencoding()
returns), but any text encoding supported by Python can be used.
See the codecs module for the list of supported encodings.
So by adding encoding='utf-8' as a parameter to the open function, the file reading and writing is all done as utf8 (which is also now the default encoding of everything done in Python.)
So, I've found a solution for what I'm looking for, which is:
print open('f2').read().decode('string-escape').decode("utf-8")
There are some unusual codecs that are useful here. This particular reading allows one to take UTF-8 representations from within Python, copy them into an ASCII file, and have them be read in to Unicode. Under the "string-escape" decode, the slashes won't be doubled.
This allows for the sort of round trip that I was imagining.
This works for reading a file with UTF-8 encoding in Python 3.2:
import codecs
f = codecs.open('file_name.txt', 'r', 'UTF-8')
for line in f:
print(line)
# -*- encoding: utf-8 -*-
# converting a unknown formatting file in utf-8
import codecs
import commands
file_location = "jumper.sub"
file_encoding = commands.getoutput('file -b --mime-encoding %s' % file_location)
file_stream = codecs.open(file_location, 'r', file_encoding)
file_output = codecs.open(file_location+"b", 'w', 'utf-8')
for l in file_stream:
file_output.write(l)
file_stream.close()
file_output.close()
Aside from codecs.open(), io.open() can be used in both 2.x and 3.x to read and write text files. Example:
import io
text = u'á'
encoding = 'utf8'
with io.open('data.txt', 'w', encoding=encoding, newline='\n') as fout:
fout.write(text)
with io.open('data.txt', 'r', encoding=encoding, newline='\n') as fin:
text2 = fin.read()
assert text == text2
To read in an Unicode string and then send to HTML, I did this:
fileline.decode("utf-8").encode('ascii', 'xmlcharrefreplace')
Useful for python powered http servers.
Well, your favorite text editor does not realize that \xc3\xa1 are supposed to be character literals, but it interprets them as text. That's why you get the double backslashes in the last line -- it's now a real backslash + xc3, etc. in your file.
If you want to read and write encoded files in Python, best use the codecs module.
Pasting text between the terminal and applications is difficult, because you don't know which program will interpret your text using which encoding. You could try the following:
>>> s = file("f1").read()
>>> print unicode(s, "Latin-1")
Capitán
Then paste this string into your editor and make sure that it stores it using Latin-1. Under the assumption that the clipboard does not garble the string, the round trip should work.
You have stumbled over the general problem with encodings: How can I tell in which encoding a file is?
Answer: You can't unless the file format provides for this. XML, for example, begins with:
<?xml encoding="utf-8"?>
This header was carefully chosen so that it can be read no matter the encoding. In your case, there is no such hint, hence neither your editor nor Python has any idea what is going on. Therefore, you must use the codecs module and use codecs.open(path,mode,encoding) which provides the missing bit in Python.
As for your editor, you must check if it offers some way to set the encoding of a file.
The point of UTF-8 is to be able to encode 21-bit characters (Unicode) as an 8-bit data stream (because that's the only thing all computers in the world can handle). But since most OSs predate the Unicode era, they don't have suitable tools to attach the encoding information to files on the hard disk.
The next issue is the representation in Python. This is explained perfectly in the comment by heikogerlach. You must understand that your console can only display ASCII. In order to display Unicode or anything >= charcode 128, it must use some means of escaping. In your editor, you must not type the escaped display string but what the string means (in this case, you must enter the umlaut and save the file).
That said, you can use the Python function eval() to turn an escaped string into a string:
>>> x = eval("'Capit\\xc3\\xa1n\\n'")
>>> x
'Capit\xc3\xa1n\n'
>>> x[5]
'\xc3'
>>> len(x[5])
1
As you can see, the string "\xc3" has been turned into a single character. This is now an 8-bit string, UTF-8 encoded. To get Unicode:
>>> x.decode('utf-8')
u'Capit\xe1n\n'
Gregg Lind asked: I think there are some pieces missing here: the file f2 contains: hex:
0000000: 4361 7069 745c 7863 335c 7861 316e Capit\xc3\xa1n
codecs.open('f2','rb', 'utf-8'), for example, reads them all in a separate chars (expected) Is there any way to write to a file in ASCII that would work?
Answer: That depends on what you mean. ASCII can't represent characters > 127. So you need some way to say "the next few characters mean something special" which is what the sequence "\x" does. It says: The next two characters are the code of a single character. "\u" does the same using four characters to encode Unicode up to 0xFFFF (65535).
So you can't directly write Unicode to ASCII (because ASCII simply doesn't contain the same characters). You can write it as string escapes (as in f2); in this case, the file can be represented as ASCII. Or you can write it as UTF-8, in which case, you need an 8-bit safe stream.
Your solution using decode('string-escape') does work, but you must be aware how much memory you use: Three times the amount of using codecs.open().
Remember that a file is just a sequence of bytes with 8 bits. Neither the bits nor the bytes have a meaning. It's you who says "65 means 'A'". Since \xc3\xa1 should become "à" but the computer has no means to know, you must tell it by specifying the encoding which was used when writing the file.
The \x.. sequence is something that's specific to Python. It's not a universal byte escape sequence.
How you actually enter in UTF-8-encoded non-ASCII depends on your OS and/or your editor. Here's how you do it in Windows. For OS X to enter a with an acute accent you can just hit option + E, then A, and almost all text editors in OS X support UTF-8.
You can also improve the original open() function to work with Unicode files by replacing it in place, using the partial function. The beauty of this solution is you don't need to change any old code. It's transparent.
import codecs
import functools
open = functools.partial(codecs.open, encoding='utf-8')
I was trying to parse iCal using Python 2.7.9:
from icalendar import Calendar
But I was getting:
Traceback (most recent call last):
File "ical.py", line 92, in parse
print "{}".format(e[attr])
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe1' in position 7: ordinal not in range(128)
and it was fixed with just:
print "{}".format(e[attr].encode("utf-8"))
(Now it can print liké á böss.)
I found the most simple approach by changing the default encoding of the whole script to be 'UTF-8':
import sys
reload(sys)
sys.setdefaultencoding('utf8')
any open, print or other statement will just use utf8.
Works at least for Python 2.7.9.
Thx goes to https://markhneedham.com/blog/2015/05/21/python-unicodeencodeerror-ascii-codec-cant-encode-character-uxfc-in-position-11-ordinal-not-in-range128/ (look at the end).