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Best way to remove '\xad' in Python?

I'm trying to build a corpus from the .txt file found at this link.
I believe the instances of \xad are supposedly 'soft-hyphens', but do not appear to be read correctly under UTF-8 encoding. I've tried encoding the .txt file as iso8859-15, using the code:
with open('Harry Potter 3 - The Prisoner Of Azkaban.txt', 'r',
encoding='iso8859-15') as myfile:
data=myfile.read().replace('\n', '')
data2 = data.split(' ')
This returns an array of 'words', but '\xad' remains attached to many entries in data2. I've tried
data_clean = data.replace('\\xad', '')
and
data_clean = data.replace('\\xad|\\xad\\xad','')
but this doesn't seem to remove the instances of '\xad'. Has anyone ran into a similar problem before? Ideally I'd like to encode this data as UTF-8 to avail of the nltk library, but it won't read the file with UTF-8 encoding as I get the following error:
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xad in position 471: invalid start byte
Any help would be greatly appreciated!
Additional context: This is a recreational project with the aim of being able to generate stories based on the txt file. Everything I've generated thus far has been permeated with '\xad', which ruins the fun!

Your file almost certainly has actual U+00AD soft-hyphen characters in it.
These are characters that mark places where a word could be split when fitting lines to a page. The idea is that the soft hyphen is invisible if the word doesn't need to be split, but printed the same as a U+2010 normal hyphen if it does.
Since you don't care about rendering this text in a book with nicely flowing text, you're never going to hyphenate anything, so you just want to remove these characters.
The way to do this is not to fiddle with the encoding. Just remove them from the Unicode text, using whichever of these you find most readable:
data = data.replace('\xad', '')
data = data.replace('\u00ad', '')
data = data.replace('\N{SOFT HYPHEN}', '')
Notice the single backslash. We're not replacing a literal backslash, x, a, d, we're replacing a literal soft-hyphen character, that is, the character whose code point is hex 0xad.
You can either do this to the whole file before splitting into words, or do it once per word after splitting.
Meanwhile, you seem to be confused about what encodings are and what to do with them:
I've tried encoding the .txt file as iso8859-15
No, you've tried decoding the file as ISO-8859-15. It's not clear why you tried ISO-8859-15 in the first place. But, since the ISO-8859-15 encoding for the character '\xad' is the byte b'\xad', maybe that's correct.
Ideally I'd like to encode this data as UTF-8 to avail of the nltk library
But NLTK doesn't want UTF-8 bytes, it wants Unicode strings. You don't need to encode it for that.
Plus, you're not trying to encode your Unicode text to UTF-8, you're trying to decode your bytes from UTF-8. If that's not what those bytes are… if you're lucky, you'll get an error like this one; if not, you'll get mojibake that you don't notice until you've screwed up a 500GB corpus and thrown away the original data.1
1. UTF-8 is specifically designed so you'll get early errors whenever possible. In this case, reading ISO-8859-15 text with soft hyphens as if it were UTF-8 raises exactly the error you're seeing, but reading UTF-8 text with soft hyphens as if it were ISO-8859-15 will silently succeed, but with an extra 'Â' character before each soft hyphen. The error is usually more helpful.

Identify garbage unicode string using python

My script is reads data from csv file, the csv file can have multiple strings of English or non English words.
Some time the text file has garbage strings , i want to identify those string and skip those string and process others
doc = codecs.open(input_text_file, "rb",'utf_8_sig')
fob = csv.DictReader(doc)
for row, entry in enumerate(f):
if is_valid_unicode_str(row['Name']):
process_futher
def is_valid_unicode_str(value):
try:
function
return True
except UnicodeEncodeError:
return false
csv input:
"Name"
"袋è¢âdcx€¹Ã¤Â¸Å½Ã¦Å“‹å‹们çâ€ÂµÃ¥Â­Âå•â€"
"元大寶來證券"
"John Dove"
I want to defile function is_valid_unicode_str() which will identify the garbage string and process valid one only.
I tried to use decode is but it doesnt failed while decoding garbage strings
value.decode('utf8')
The expected output are string with Chinese and English string to be process
could you please guide me how can i implement function to filter valid Unicode files?.

(ftfy developer here)
I've figured out that the text is likely to be '袋袋与朋友们电子商'. I had to guess at the characters 友, 子, and 商, because some unprintable characters are characters missing in the string in your question. When guessing, I picked the most common character from the small number of possibilities. And I don't know where the "dcx" goes or why it's there.
Google Translate is not very helpful here but it seems to mean something about e-commerce.
So here's everything that happened to your text:
It was encoded as UTF-8 and decoded incorrectly as sloppy-windows-1252, twice
It had the letters "dcx" inserted into the middle of a UTF-8 sequence
Characters that don't exist in windows-1252 -- with byte values 81, 8d, 8f, 90, and 9d -- were removed
A non-breaking space (byte value a0) was removed from the end
If just the first problem had happened, ftfy.fix_text_encoding would be able to fix it. It's possible that the remaining problems just happened while you were trying to get the string onto Stack Overflow.
So here's my recommendation:
Find out who keeps decoding the data incorrectly as sloppy-windows-1252, and get them to decode it as UTF-8 instead.
If you end up with a string like this again, try ftfy.fix_text_encoding on it.

You have Mojibake strings; text encoded to one (correct) codec, then decoded as another.
In this case, your text was decoded with the Windows 1252 codepage; the U+20AC EURO SIGN in the text is typical of CP1252 Mojibakes. The original encoding could be one of the GB* family of Chinese encodings, or a multiple roundtrip UTF-8 - CP1252 Mojibake. Which one I cannot determine, I cannot read Chinese, nor do I have your full data; CP1252 Mojibakes include un-printable characters like 0x81 and 0x8D bytes that might have gotten lost when you posted your question here.
I'd install the ftfy project; it won't fix GB* encodings (I requested the project add support), but it includes a new codec called sloppy-windows-1252 that'll let you reverse an erroneous decode with that codec:
>>> import ftfy # registers extra codecs on import
>>> text = u'袋è¢âdcx€¹Ã¤Â¸Å½Ã¦Å“‹å‹们çâ€ÂµÃ¥Â­Âå•â€'
>>> print text.encode('sloppy-windows-1252').decode('gb2312', 'replace')
猫垄�姑�⑩dcx�盲赂沤忙��姑ヂ�姑ぢ宦�р�得ヂ�氓�⑩�
>>> print text.encode('sloppy-windows-1252').decode('gbk', 'replace')
猫垄鈥姑�⑩dcx�盲赂沤忙艙鈥姑ヂ鈥姑ぢ宦�р�得ヂ�氓鈥⑩�
>>> print text.encode('sloppy-windows-1252').decode('gb18030', 'replace')
猫垄鈥姑⑩dcx�盲赂沤忙艙鈥姑ヂ鈥姑ぢ宦р�得ヂ氓鈥⑩�
>>> print text.encode('sloppy-windows-1252').decode('utf8', 'ignore').encode('sloppy-windows-1252').decode('utf8', 'replace')
袋�dcx与朋�们���
The � U+FFFD REPLACEMENT CHARACTER shows the decoding wasn't entirely successful, but that could be due to the fact that your copied string here is missing anything not printable or using the 0x81 or 0x8D bytes.
You can try to fix your data this way; from the file data, try to decode to one of the GB* codecs after encoding to sloppy-windows-1252, or roundtrip from UTF-8 twice and see what fits best.
If that's not good enough (you cannot fix the data) you can use the ftfy.badness.sequence_weirdness() function to try and detect the issue:
>>> from ftfy.badness import sequence_weirdness
>>> sequence_weirdness(text)
9
>>> sequence_weirdness(u'元大寶來證券')
0
>>> sequence_weirdness(u'John Dove')
0
Mojibakes score high on the sequence weirdness scale. You'd could try and find an appropriate threshold for your data by which time you'd call the data most likely to be corrupted.
However, I think we can use a non-zero return value as a starting point for another test. English text should score 0 on that scale, and so should Chinese text. Chinese mixed with English can still score over 0, but you could not then encode that Chinese text to the CP-1252 codec while you can with the broken text:
from ftfy.badness import sequence_weirdness
def is_valid_unicode_str(text):
if not sequence_weirdness(text):
# nothing weird, should be okay
return True
try:
text.encode('sloppy-windows-1252')
except UnicodeEncodeError:
# Not CP-1252 encodable, probably fine
return True
else:
# Encodable as CP-1252, Mojibake alert level high
return False

Python Unicode Handling Errors - How To Simply Remove Unicode

There are literally dozens, maybe even hundreds of questions on this site about unicode handling errors with python. Here is an example of what I am talking about:
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 2310: ordinal not in range(128)
A great many of the questions indicate that the OP just wants the offending content to GO AWAY. The responses they receive are uniformly full of mumbo jumbo about codecs, character sets, and all sorts of things that do not address this one basic question:
"I am trying to process a text file with some unicode in it, I could not possibly care any less what this stuff is, it is just noise in the context of the problem I am trying to solve."
So, I have a file with a zillion JSON encoded tweets, I have no interest at all in these special characters, I want them REMOVED from the line.
fh = open('file-full-of-unicode.txt')
for line in fh:
print zap_unicode(line)
Given a variable called 'line', how do I simply print it minus any unicode it might contain?
There, I have repeated the question in several different fashions so it can not be misconstrued - unicode is junk in the context of what I am trying to do, I want to convert it to something innocuous or simply remove it entirely. How is this most easily accomplished?

You can do line.decode('ascii', 'ignore'). This will decode as ASCII everything that it can, ignoring any errors.
However, if you do this, prepare for pain. Unicode exists for a reason. Throwing away parts of your data without even knowing what you're throwing away will almost always cause problems down the road. It's like saying "I don't care if some of the gizmos inside my car engine don't work, I just want to drive it. Just take out anything that doesn't work!" That's all well and good until it explodes.

The problem can't "go away", the code that can't handle unicodes properly must be fixed. There is no trivial way to do this, but the simplest way is to decode the bytes on input to make sure that the application is using text everywhere.

as #BrenBarn suggested the result will be spurious english words...
my suggestion is why not consider removing entire word which contains a unicode character
i.e a word is space+characters+space if characters has a unicode character then remove all character after previous space and before next space.. the result will be much better than removing just unicode characters..
if you just want to remove names (#username) and tags (#tags) you can use a filter ([#,#,..]) instead of brute forcibly searching for all unicode characters..
I have low reputation so can't comment, so made it as an answer.. :-(

Python Encoding issue

Why am I getting this issue? and how do I resolve it?
UnicodeDecodeError: 'utf8' codec can't decode byte 0x92 in position 24: unexpected code byte
Thank you

Somewhere, perhaps subtly, you are asking Python to turn a stream of bytes into a "string" of characters.
Don't think of a string as "bytes". A string is a list of numbers, each number having an agreed meaning in Unicode. (#65 = Latin Capital A. #19968 = Chinese Character "One"/"First") .
There are many methods of encoding a list of Unicode entities into a stream of bytes. Python is assuming your stream of bytes is the result of a particular such method, called "UTF-8".
However, your stream of bytes has data that does not correspond to that method. Thus the error is raised.
You need to figure out the encoding of the stream of bytes, and tell Python that encoding.
It's important to know if you're using Python 2 or 3, and the code leading up to this exception to see where your bytes came from and what the appropriate way to deal with them is.
If it's from reading a file, you can explicity deal with the bytes read. But you must be sure of the file encoding.
If it's from a string that is part of your source code, then Python is assuming the "wrong thing" about your source files... perhaps $LC_ALL or $LANG needs to be set. This is a good time to firmly understand the concept of encoding, and how text editors choose an encoding to write, and what is standard for your language and operating system.

In addition to what Joe said, chardet is a useful tool to detect encoding of the source data.

Somewhere you have a plain string encoded as "Windows-1252" (or "cp1252") containing a "RIGHT SINGLE QUOTATION MARK" (’) instead of an APOSTROPHE ('). This could come from a file you read, or even in a Python source file of yours; you could be running Python 2.x and have a # -*- coding: utf8 -*- line somewhere near the script's beginning, or you could be running Python 3.x.
You don't give enough data; however, somewhere you have a cp1252-encoded string, which you try (explicitly or implicitly) to decode to unicode as utf-8. This won't work.
Give us more info, and we'll try again to help you.
Joe Koberg's answer reminded me of an older answer of mine, which some people have found helpful: Python UnicodeDecodeError - Am I misunderstanding encode?

Unicode utf-8/utf-16 encoding in Python

In python:
u'\u3053\n'
Is it utf-16?
I'm not really aware of all the unicode/encoding stuff, but this type of thing is coming up in my dataset,
like if I have a=u'\u3053\n'.
print gives an exception and
decoding gives an exception.
a.encode("utf-16") > '\xff\xfeS0\n\x00'
a.encode("utf-8") > '\xe3\x81\x93\n'
print a.encode("utf-8") > πüô
print a.encode("utf-16") >  ■S0
What's going on here?

It's a unicode character that doesn't seem to be displayable in your terminals encoding. print tries to encode the unicode object in the encoding of your terminal and if this can't be done you get an exception.
On a terminal that can display utf-8 you get:
>>> print u'\u3053'
こ
Your terminal doesn't seem to be able to display utf-8, else at least the print a.encode("utf-8") line should produce the correct character.

You ask:
u'\u3053\n'
Is it utf-16?
The answer is no: it's unicode, not any specific encoding. utf-16 is an encoding.
To print a Unicode string effectively to your terminal, you need to find out what encoding that terminal is willing to accept and able to display. For example, the Terminal.app on my laptop is set to UTF-8 and with a rich font, so:
(source: aleax.it)
...the Hiragana letter displays correctly. On a Linux workstation I have a terminal program that keeps resetting to Latin-1 so it would mangle things somewhat like yours -- I can set it to utf-8, but it doesn't have huge number of glyphs in the font, so it would display somewhat-useless placeholder glyphs instead.

Character U+3053 "HIRAGANA LETTER KO".
The \xff\xfe bit at the start of the UTF-16 binary format is the encoded byte order mark (U+FEFF), then "S0" is \x5e\x30, then there's the \n from the original string. (Each of the characters has its bytes "reversed" as it's using little endian UTF-16 encoding.)
The UTF-8 form represents the same Hiragana character in three bytes, with the bit pattern as documented here.
Now, as for whether you should really have it in your data set... where is this data coming from? Is it reasonable for it to have Hiragana characters in it?

Here's the Unicode HowTo Doc for Python 2.6.2:
http://docs.python.org/howto/unicode.html
Also see the links in the Reference section of that document for other explanations, including one by Joel Spolsky.