I try to write a "string" to a file and get the following error message:
UnicodeEncodeError: 'ascii' codec can't encode character u'\xcd' in position 6: ordinal not in range(128)
I tried the following methods:
print >>f, txt
print >>f, txt.decode('utf-8')
print >>f, txt.encode('utf-8')
None of them work. I have the same error message.
What is the idea behind encoding and decoding? If I have a unicode object can I write it to the file directly or I need to transform it to a string?
How can I find out what codding is used? How can I know if it is utf-8 or ascii or something else?
ADDED
I think I have just managed to save a string into a file. print >>f, txt as well as print >>f, txt.decode('utf-8') did not work but print >>f, txt.encode('utf-8') works. I get no error message and I see Chinese characters in my file.
I recently posted another answer that addresses this very issue. Key quote:
For a good overview of the difference, read one of Joel's articles, but the gist is that bytes are, well, bytes (groups of 8 bits without any further meaning attached), whereas characters are the things that make up strings of text. Encoding turns characters into bytes, and decoding turns bytes back into characters.
In Python 2, unicode objects are character strings. Regular str objects can be either character strings or byte strings. (Pro tip: use Python 3, it makes keeping track a lot easier.)
You should be passing character strings (not byte strings) to print, but you will need to be sure that those character strings can be encoded by the codec (such as ASCII or UTF-8) associated with the destination file object f. As part of the output process, Python encodes the string for you. If the string contains characters that cannot be encoded by the file object's codec, you will get errors like the one you're seeing.
Without knowing what is in your txt object I can't be more specific.
I think you need to use codecs library:
import codecs
file = codecs.open("test.txt", "w", "utf-8")
file.write(u'\xcd')
file.close()
Works fine.
The Story of Encoding/Decoding:
In the past, there were only about ~60 characters available in computers (including upper-case and lower-case letters + numbers + some special characters). So only 1 byte was enough to assign a unique number to each letter. Assigning numbers to letters for storing in memory is called encoding. This one byte encoding that is used in python by default is named ASCII.
With growth of computers in the world, we need to have more letters and characters in computer. So 1 byte is not enough. Different encoding schemes appeared. Unicode is one of the famous. The character that you are trying to store in your file is a Unicode character and it need 2 bytes, So you must explicitly indicate to Python that you don't want to use the default encoding, i.e. the ASCII (because you need 2 bytes for this character).
Related
I'm creating an compression / encryption program that utilises (nearly) all unicode characters, and then writes the data to a file. However, to write to the file, I need to encode the characters to bytes. However, when I do so, It gives this error:
unicodeencodeerror: 'utf-8' codec can't encode character '\udd7d' in position 1323: surrogates not allowed
I've tried all of the built-in python codecs, none of them work, except for 'utf-7', however, this simply encodes the unicode to base64, which defeats the object of what I'm trying to achieve.
file = open(str(file_name.capitalize()) + ".Unicode_File","wb")
file.write(unicode_madness.encode("utf-8"))
file.close()
I expect it to write the variable 'unicode_madness' to the file, which it does, however sometimes it tries to use a surrogate unicode character.
To resolve this, I either need to be able to avoid the surrogate characters (while keeping the compression lossless), or I need to find out which unicode characters use surrogates, and I can adjust the program accordingly.
Thanks for any help!
I am working with Russian words written in the Cyrillic orthography. Everything is working fine except for how many (but not all) of the Cyrillic characters are encoded as two characters when in an str. For instance:
>>>print ["ё"]
['\xd1\x91']
This wouldn't be a problem if I didn't want to index string positions or identify where a character is and replace it with another (say "e", without the diaeresis). Obviously, the 2 "characters" are treated as one when prefixed with u, as in u"ё":
>>>print [u"ё"]
[u'\u0451']
But the strs are being passed around as variables, and so can't be prefixed with u, and unicode() gives a UnicodeDecodeError (ascii codec can't decode...).
So... how do I get around this? If it helps, I am using python 2.7
There are two possible situations here.
Either your str represents valid UTF-8 encoded data, or it does not.
If it represents valid UTF-8 data, you can convert it to a Unicode object by using mystring.decode('utf-8'). After it's a unicode instance, it will be indexed by character instead of by byte, as you have already noticed.
If it has invalid byte sequences in it... You're in trouble. This is because the question of "which character does this byte represent?" no longer has a clear answer. You're going to have to decide exactly what you mean when you say "the third character" in the presence of byte sequences that don't actually represent a particular Unicode character in UTF-8 at all...
Perhaps the easiest way to work around the issue would be to use the ignore_errors flag to decode(). This will entirely discard invalid byte sequences and only give you the "correct" portions of the string.
These are actually different encodings:
>>>print ["ё"]
['\xd1\x91']
>>>print [u"ё"]
[u'\u0451']
What you're seeing is the __repr__'s for the elements in the lists. Not the __str__ versions of the unicode objects.
But the strs are being passed around as variables, and so can't be
prefixed with u
You mean the data are strings, and need to be converted into the unicode type:
>>> for c in ["ё"]: print repr(c)
...
'\xd1\x91'
You need to coerce the two-byte strings into double-byte width unicode:
>>> for c in ["ё"]: print repr(unicode(c, 'utf-8'))
...
u'\u0451'
And you'll see with this transform they're perfectly fine.
To convert bytes into Unicode, you need to know the corresponding character encoding and call bytes.decode:
>>> b'\xd1\x91'.decode('utf-8')
u'\u0451'
The encoding depends on the data source. It can be anything e.g., if the data comes from a web page; see A good way to get the charset/encoding of an HTTP response in Python
Don't use non-ascii characters in a bytes literal (it is explicitly forbidden in Python 3). Add from __future__ import unicode_literals to treat all "abc" literals as Unicode literals.
Note: a single user-perceived character may span several Unicode codepoints e.g.:
>>> print(u'\u0435\u0308')
ё
Ok I've found a lot of threads about how to convert a string from something like "/xe3" to "ã" but how the hell am I supposed to do it the other way around?
My concrete problem: I am using an API and everything works great except I provide some strings which then result in a json object. The result is sorted after the names (strings) I provided however they are returned as their unicode representation and as json APIs always work in pure strings. So all I need is a way to get from "ã" to "/xe3" but it can't for the love of god get it to work.
Every type of encoding or decoding I try either defaults back to a normal string, a string without that character, a string with a plain A or an unicode error that ascii can't decode it. (<- this was due to a horrible shell setup. Yay for old me.)
All I want is the plain encoded string!
(yea no not at all past me. All you want is the unicode representation of a character as string)
PS: All in python if that wasn't obvious from the title already.
Edit: Even though this is quite old I wanted to update this to not completely embarrass myself in the future.
The issue was an API which provided unicode representations of characters as string as a response. All I wanted to do was checking if they are the same however I had major issues getting python to interpret the string as unicode especially since those characters were just some inside of a longer text partially with backslashes.
This did help but I just stumbled across this horribly written question and just couldn't leave it like that.
"\xe3" in python is a string literal that represents a single byte with value 227:
>>> print len("\xe3")
1
>>> print ord("\xe3")
227
This single byte represents the 'ã' character in the latin-1 encoding (http://en.wikipedia.org/wiki/ISO/IEC_8859-1).
"ã" in python is a string literal consisting of two bytes: 0xC3, 0xA3 (195, 163):
>>> print len("ã")
2
>>> print ord("ã"[0])
195
>>> print ord("ã"[1])
163
This byte sequence is the UTF-8 encoding of the character "ã".
So, to go from "ã" in python to "\xe3", you first need to decode the utf-8 byte sequence into a python unicode string:
>>> "ã".decode("utf-8")
u'\xe3'
Now, you can take that unicode string and encode it however you like (e.g. into latin-1):
>>> "ã".decode("utf-8").encode("latin-1")
'\xe3'
Please read http://www.joelonsoftware.com/articles/Unicode.html . You should realize tehre is no such a thing as "a plain encoded string". There is "an encoded string in a given text encoding". So you are really in need to understand the better the concepts of Unicode.
Among other things, this is plain wrong: "The result is sorted after the names (strings) I provided however they are returned in encoded form." JSON uses Unicode, so you get the string in a decoded form.
Since I assume you are, perhaps unknowingly, working with UTF-8, you should be aware that \xe3 is the Unicode code point for the character ã. Not to be mistaken for the actual bytes that UTF-8 uses to reference that code point:
http://hexutf8.com/?q=U+e3
I.e. UTF-8 maps the byte sequence c3 a3 to the code point U+e3 which represents the character ã.
UTF-16 maps a different byte sequence, 00 e3 to that exact same code point. (Note how much simpler, but less space efficient the UTF-16 encoding is...)
I have a definition that builds a string composed of UTF-8 encoded characters. The output files are opened using 'w+', "utf-8" arguments.
However, when I try to x.write(string) I get the UnicodeEncodeError: 'ascii' codec can't encode character u'\ufeff' in position 1: ordinal not in range(128)
I assume this is because normally for example you would do `print(u'something'). But I need to use a variable and the quotations in u'_' negate that...
Any suggestions?
EDIT: Actual code here:
source = codecs.open("actionbreak/" + target + '.csv','r', "utf-8")
outTarget = codecs.open("actionbreak/" + newTarget, 'w+', "utf-8")
x = str(actionT(splitList[0], splitList[1]))
outTarget.write(x)
Essentially all this is supposed to be doing is building me a large amount of strings that look similar to this:
[日木曜 Deliverables]= CASE WHEN things = 11
THEN C ELSE 0 END
Are you using codecs.open()? Python 2.7's built-in open() does not support a specific encoding, meaning you have to manually encode non-ascii strings (as others have noted), but codecs.open() does support that and would probably be easier to drop in than manually encoding all the strings.
As you are actually using codecs.open(), going by your added code, and after a bit of looking things up myself, I suggest attempting to open the input and/or output file with encoding "utf-8-sig", which will automatically handle the BOM for UTF-8 (see http://docs.python.org/2/library/codecs.html#encodings-and-unicode, near the bottom of the section) I would think that would only matter for the input file, but if none of those combinations (utf-8-sig/utf-8, utf-8/utf-8-sig, utf-8-sig/utf-8-sig) work, then I believe the most likely situation would be that your input file is encoded in a different Unicode format with BOM, as Python's default UTF-8 codec interprets BOMs as regular characters so the input would not have an issue but output could.
Just noticed this, but... when you use codecs.open(), it expects a Unicode string, not an encoded one; try x = unicode(actionT(splitList[0], splitList[1])).
Your error can also occur when attempting to decode a unicode string (see http://wiki.python.org/moin/UnicodeEncodeError), but I don't think that should be happening unless actionT() or your list-splitting does something to the Unicode strings that causes them to be treated as non-Unicode strings.
In python 2.x there are two types of string: byte string and unicode string. First one contains bytes and last one - unicode code points. It is easy to determine, what type of string it is - unicode string starts with u:
# byte string
>>> 'abc'
'abc'
# unicode string:
>>> u'abc абв'
u'abc \u0430\u0431\u0432'
'abc' chars are the same, because the are in ASCII range. \u0430 is a unicode code point, it is out of ASCII range. "Code point" is python internal representation of unicode points, they can't be saved to file. It is needed to encode them to bytes first. Here how encoded unicode string looks like (as it is encoded, it becomes a byte string):
>>> s = u'abc абв'
>>> s.encode('utf8')
'abc \xd0\xb0\xd0\xb1\xd0\xb2'
This encoded string now can be written to file:
>>> s = u'abc абв'
>>> with open('text.txt', 'w+') as f:
... f.write(s.encode('utf8'))
Now, it is important to remember, what encoding we used when writing to file. Because to be able to read the data, we need to decode the content. Here what data looks like without decoding:
>>> with open('text.txt', 'r') as f:
... content = f.read()
>>> content
'abc \xd0\xb0\xd0\xb1\xd0\xb2'
You see, we've got encoded bytes, exactly the same as in s.encode('utf8'). To decode it is needed to provide coding name:
>>> content.decode('utf8')
u'abc \u0430\u0431\u0432'
After decode, we've got back our unicode string with unicode code points.
>>> print content.decode('utf8')
abc абв
xgord is right, but for further edification it's worth noting exactly what \ufeff means. It's known as a BOM or a byte order mark and basically it's a callback to the early days of unicode when people couldn't agree which way they wanted their unicode to go. Now all unicode documents are prefaced with either an \ufeff or an \uffef depending on which order they decide to arrange their bytes in.
If you hit an error on those characters in the first location you can be sure the issue is that you are not trying to decode it as utf-8, and the file is probably still fine.
I'm writing a Python script to process some music data. It's supposed to merge two separate databases by comparing their entries and matching them up. It's almost working, but fails when comparing strings containing special characters (i.e. accented letters). I'm pretty sure it's a ASCII vs. Unicode encoding issue, as I get the error:
"Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal"
I realize I could use regular expressions to remove the offending characters, but I'm processing a lot of data and relying too much on regexes makes my program grindingly slow. Is there a way to have Python properly compare these strings? What is going on here--is there a way to tell whether it's storing my strings as ASCII or Unicode?
EDIT 1: I'm using Python v2.6.6. After checking the types, I've discovered that one database spits out me Unicode strings and one gives ASCII. So that's probably the problems. I'm trying to convert the ASCII strings from the second database to Unicode with a line like
line = unicode(f.readline().decode(latin_1).encode(utf_8))
but this gives an error like:
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 41: ordinal not in range(128)
I'm not sure why the 'ascii' codec is complaining since I'm trying to decode from ASCII. Can anyone help?
Unicode vs Bytes
First, some terminology. There are two types of strings, encoded and decoded:
Encoded. This is what's stored on disk. To Python, it's a bunch of 0's and 1's that you might treat like ASCII, but it could be anything -- binary data, a JPEG image, whatever. In Python 2.x, this is called a "string" variable. In Python 3.x, it's more accurately called a "bytes" variable.
Decoded. This is a string of actual characters. They could be encoded to 8-bit ASCII strings, or it could be encoded to 32-bit Chinese characters. But until it's time to convert to an encoded variable, it's just a Unicode string of characters.
What this means to you
So here's the thing. You said you were getting one ASCII variable and one Unicode variable. That's actually not true.
You have one variable that's a string of bytes -- ones and zeros, presumably in sets of 8. This is the variable you assumed, incorrectly, to be ASCII.
You have another variable that's Unicode data -- numbers, letters, and symbols.
Before you compare the string of bytes to a Unicode string of characters, you have to make some assumptions. In your case, Python (and you) assumed that the string of bytes was ASCII encoded. That worked fine until you came across a character that wasn't ASCII -- a character with an accent mark.
So you need to find out what that string of bytes is encoded as. It might be latin1. If it is, you want to do this:
if unicode_variable == string_variable.decode('latin1')
Latin1 is basically ASCII plus some extended characters like Ç and Â.
If your data is in Latin1, that's all you need to do. But if your string of bytes is encoded in something else, you'll need to figure out what encoding that is and pass it to decode().
The bottom line is, there's no easy answer, unless you know (or make some assumptions) about the encoding of your input data.
What I would do
Try running var.decode('latin1') on your string of bytes. That will give you a Unicode variable. If that works, and the data looks correct (ie, characters with accent marks look like they belong), roll with it.
Oh, and if latin1 doesn't parse or doesn't look right, try utf8 -- another common encoding.
You might need to preprocess the databases and convert everything into UTF-8. My guess is that you've got Latin-1 accented characters in some entries.
As to your question, the only way to know for sure is to look. Have your script spit out those that don't compare, and look up the character codes. Or just try string.decode('latin1').encode('utf8') and see what happens.
Converting both to unicode should help:
if unicode(str1) == unicode(str2):
print "same"
To find out whether YOU (not it) are storing your strings as str objects or unicode objects, print type(your_string).
You can use print repr(your_string) to show yourself (and us) unambiguously what is in your string.
By the way, exactly what version of Python are you using, on what OS? If Python 3.x, use ascii() instead of repr().