Develop Reference

python cleaning high or non-ascii out of a file [duplicate]

I'm working on a series of parsers where I get a bunch of tracebacks from my unit tests like:
File "c:\Python31\lib\encodings\cp1252.py", line 23, in decode
return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 112: character maps to <undefined>
The files are opened with open() with no extra arguemnts. Can I pass extra arguments to open() or use something in the codec module to open these differently?
This came up with code that was written in Python 2 and converted to 3 with the 2to3 tool.
UPDATE: it turns out this is a result of feeding a zipfile into the parser. The unit test actually expects this to happen. The parser should recognize it as something that can't be parsed. So, I need to change my exception handling. In the process of doing that now.

Position 0x81 is unassigned in Windows-1252 (aka cp1252). It is assigned to U+0081 HIGH OCTET PRESET (HOP) control character in Latin-1 (aka ISO 8859-1). I can reproduce your error in Python 3.1 like this:
>>> b'\x81'.decode('cp1252')
Traceback (most recent call last):
...
UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 0: character maps to <undefined>
or with an actual file:
>>> open('test.txt', 'wb').write(b'\x81\n')
2
>>> open('test.txt').read()
Traceback (most recent call last):
...
UnicodeDecodeError: 'utf8' codec can't decode byte 0x81 in position 0: unexpected code byte
Now to treat this file as Latin-1 you pass the encoding argument, like codeape suggested:
>>> open('test.txt', encoding='latin-1').read()
'\x81\n'
Beware that there are differences between Windows-1257 and Latin-1 encodings, e.g. Latin-1 doesn't have “smart quotes”. If the file you're processing is a text file, ask yourself what that \x81 is doing in it.

You can relax the error handling.
For instance:
f = open(filename, encoding="...", errors="replace")
Or:
f = open(filename, encoding="...", errors="ignore")
See the docs.
EDIT:
But are you certain that the problem is in reading the file? Could it be that the exception happens when something is written to the console? Check http://wiki.python.org/moin/PrintFails

All files are "not Unicode". Unicode is an internal representation which must be encoded. You need to determine for each file what encoding has been used, and specify that where necessary when the file is opened.
As the traceback and error message indicate, the file in question is NOT encoded in cp1252.
If it is encoded in latin1, the "\x81" that it is complaining about is a C1 control character that doesn't even have a name (in Unicode). Consider latin1 extremely unlikely to be valid.
You say "some of the files are parsed with xml.dom.minidom" -- parsed successfully or unsuccessfully?
A valid XML file should declare its encoding (default is UTF-8) in the first line, and you should not need to specify an encoding in your code. Show us the code that you are using to do the xml.dom.minidom parsing.
"others read directly as iterables" -- sample code please.
Suggestion: try opening some of each type of file in your browser. Then click View and click Character Encoding (Firefox) or Encoding (Internet Explorer). What encoding has the browser guessed [usually reliably]?
Other possible encoding clues: What languages are used in the text in the files? Where did you get the files from?
Note: please edit your question with clarifying information; don't answer in the comments.

Python write (iPhone) Emoji to a file

I have been trying to write a simple script that can save user input (originating from an iPhone) to a text file. The issue I'm having is that when a user uses an Emoji icon, it breaks the whole thing.
OS: Ubuntu
Python Version: 2.7.3
My code currently looks like this
f = codecs.open(path, "w+", encoding="utf8")
f.write("Desc: " + json_obj["description"])
f.close()
When an Emoji character is passed in the description variable, I get the error:
UnicodeEncodeError: 'ascii' codec can't encode characters in position 7-8: ordinal not in range(128)
Any possible help is appreciated.

The most likely problem here is that json_obj["description"] is actually a UTF-8-encoded str, not a unicode. So, when you try to write it to a codecs-wrapped file, Python has to decode it from str to unicode so it can re-encode it. And that's the part that fails, because that automatic decoding uses sys.getdefaultencoding(), which is 'ascii'.
For example:
>>> f = codecs.open('emoji.txt', 'w+', encoding='utf-8')
>>> e = u'\U0001f1ef'
>>> print e
🇯
>>> e
u'\U0001f1ef'
>>> f.write(e)
>>> e8 = e.encode('utf-8')
>>> e8
'\xf0\x9f\x87\xaf'
>>> f.write(e8)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xf0 in position 0: ordinal not in range(128)
There are two possible solutions here.
First, you can explicitly decode everything to unicode as early as possible. I'm not sure where your json_obj is coming from, but I suspect it's not actually the stdlib json.loads, because by default, that always gives you unicode keys and values. So, replacing whatever you're using for JSON with the stdlib functions will probably solve the problem.
Second, you can leave everything as UTF-8 str objects and stay in binary mode. If you know you have UTF-8 everywhere, just open the file instead of codecs.open, and write without any encoding.
Also, you should strongly consider using io.open instead of codecs.open. It has a number of advantages, including:
Raises an exception instead of doing the wrong thing if you pass it incorrect values.
Often faster.
Forward-compatible with Python 3.
Has a number of bug fixes that will never be back-ported to codecs.
The only disadvantage is that it's not backward compatible to Python 2.5. Unless that matters to you, don't use codecs.

Python zipfile sending via suds error: "'ascii' codec can't decode byte 0x8c in position 10: ordinal not in range(128)"

I have the following error when I trying to send Zipfile content via suds method
'ascii' codec can't decode byte 0x8c in position 10: ordinal not in range(128)
Here is my code:
try:
project_archive = open(os.path.join(settings.MEDIA_ROOT, 'zip/project.zip'), "rb")
data = project_archive.read()
client = Client(settings.UPLOAD_PROJECT_WS_URL)
client.service.uploadProject(data)
except Exception as e:
return HttpResponse(e)
else:
return HttpResponse("Project was exported")

suds doesn't support soap file attachment (not last time I checked, it has been a while).
Work around here:
https://fedorahosted.org/suds/attachment/ticket/350/soap_attachments.2.py
or use a different library

Assuming that in the WSDL the argument type is xsd:base64Binary, you need to:
client.service.uploadProject(base64.b64encode(data))
In my case the sever was written in JAX-WS and the function argument type was Byte[] and Base64 worked for me

The problem seems to be simply that you are trying to read a unicode formatted file using ascii codec. Refer to http://docs.python.org/2/howto/unicode.html for the official documentation on unicode. You can also look at Unicode (UTF-8) reading and writing to files in Python for a similar discussion.
In short for your problem the following code should work:
import codecs
project_archive = codecs.open(os.path.join(settings.MEDIA_ROOT, 'zip/project.zip'),
"rb", "utf-8")
data = project_archive.read()
In the above solution its assumed that the unicode encoding used is utf-8. If some other codec (for example ISO-8859-1) is being used substitute that for the utf-8.

Why does my Python program get UnicodeDecodeError in IntelliJ but is OK from the command line?

I have a simple program that loads a .json file which contains a funny character. The program (see below) runs fine in Terminal but gets this error in IntelliJ:
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position
2: ordinal not in range(128)
The crucial code is:
with open(jsonFileName) as f:
jsonData = json.load(f)
if I replace the open with:
with open(jsonFileName, encoding='utf-8') as f:
Then it works in both IntelliJ and Terminal. I'm still new to Python and the IntelliJ plugin, and I don't understand why they're different. I thought sys.path might be different, but the output makes me think that's not the cause. Could someone please explain? Thanks!
Versions:
OS: Mac OS X 10.7.4 (also tested on 10.6.8)
Python 3.2.3 (v3.2.3:3d0686d90f55, Apr 10 2012, 11:25:50) /Library/Frameworks/Python.framework/Versions/3.2/bin/python3.2
IntelliJ: 11.1.3 Ultimate
Files (2):
1. unicode-error-demo.py
#!/usr/bin/python
import json
from pprint import pprint as pp
import sys
def main():
if len(sys.argv) is not 2:
print(sys.argv[0], "takes one arg: a .json file")
return
jsonFileName = sys.argv[1]
print("sys.path:")
pp(sys.path)
print("processing", jsonFileName)
# with open(jsonFileName) as f: # OK in Terminal, but BUG in IntelliJ: UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 2: ordinal not in range(128)
with open(jsonFileName, encoding='utf-8') as f: # OK in both
jsonData = json.load(f)
pp(jsonData)
if __name__ == "__main__":
main()
2. encode-temp.json
["™"]

The JSON .load() function expects Unicode data, not raw bytes. Python automatically tries to decode the byte string to a Unicode string for you using a default codec (in your case ASCII), and fails. By opening the file with the UTF-8 codec, Python makes an explicit conversion for you. See the open() function, which states:
In text mode, if encoding is not specified the encoding used is platform dependent.
The encoding that would be used is determined as follows:
Try os.device_encoding() to see if there is a terminal encoding.
Use locale.getpreferredencoding() function, which depends on the environment you run your code in. The do_setlocale of that function is set to False.
Use 'ASCII' as a default if both methods have returned None.
This is all done in C, but it's python equivalent would be:
if encoding is None:
encoding = os.device_encoding()
if encoding is None:
encoding = locale.getpreferredencoding(False)
if encoding is None:
encoding = 'ASCII'
So when you run your program in a terminal, os.deviceencoding() returns 'UTF-8', but when running under IntelliJ there is no terminal, and if no locale is set either, python uses 'ASCII'.
The Python Unicode HOWTO tells you all about the difference between unicode strings and bytestrings, as well as encodings. Another essential article on the subject is Joel Spolsky's Absolute Minimum Unicode knowledge article.

Python 2.x has strings and unicode strings. The basic strings are encoded with ASCII. ASCII uses only 7 bits/char, which allow to encode 128 characters, while modern UTF-8 uses up to 4 bytes/char. UTF-8 is compatible with ASCII (so that any ASCII-encoded string is a valid UTF-8 string), but not the other way round.
Apparently, your file name contains non-ASCII characters. And python by default wants to read it in as simple ASCII-encoded string, spots a non-ASCII character (its first bit is not 0 as it's 0xe2) and says, 'ascii' codec can't decode byte 0xe2 in position 2: ordinal not in range(128).
Has nothing to do with python, but still my favourite tutorial about encodings:
http://hektor.umcs.lublin.pl/~mikosmul/computing/articles/linux-unicode.html

Diacritic signs

How should I write "mąka" in Python without an exception?
I've tried var= u"mąka" and var= unicode("mąka") etc... nothing helps
I have coding definition in first line in my document, and still I've got that exception:
'utf8' codec can't decode byte 0xb1 in position 0: unexpected code byte

Save the following 2 lines into write_mako.py:
# -*- encoding: utf-8 -*-
open(u"mąka.txt", 'w').write("mąka\n")
Run:
$ python write_mako.py
mąka.txt file that contains the word mąka should be created in the current directory.
If it doesn't work then you can use chardet to detect actual encoding of the file (see chardet example usage):
import chardet
print chardet.detect(open('write_mako.py', 'rb').read())
In my case it prints:
{'confidence': 0.75249999999999995, 'encoding': 'utf-8'}

The # -- coding: -- line must specify the encoding the source file is saved in. This error message:
'utf8' codec can't decode byte 0xb1 in position 0: unexpected code byte
indicates you aren't saving the source file in UTF-8. You can save your source file in any encoding that supports the characters you are using in the source code, just make sure you know what it is and have an appropriate coding line.

What exception are you getting?
You might try saving your source code file as UTF-8, and putting this at the top of the file:
# coding=utf-8
That tells Python that the file’s saved as UTF-8.

This code works for me, saving the file as UTF-8:
v = u"mąka"
print repr(v)
The output I get is:
u'm\u0105ka'
Please copy and paste the exact error you are getting. If you are getting this error:
UnicodeEncodeError: 'charmap' codec can't encode character ... in position ...: character maps to <undefined>
Then you are trying to output the character somewhere that does not support UTF-8 (e.g. your shell's character encoding is set to something other than UTF-8).