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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.

How to determine the position from decoding error message in Python?

I keep receiving this 'Unicodedecodeerror'
UnicodeDecodeError: 'charmap' codec can't decode byte 0x8d in position 16592600: character maps to
when trying to run the following for a unicode .txt file
f=open('FY16_Query_Analysis1.txt','rU')
raw=f.read()

In short, you have to find out what encoding is used in the text file, and then specify it.
Step 2 is easy. For example, if the encoding is UTF-8:
f = open('FY16_Query_Analysis1.txt', 'r', encoding='utf8')
(As a side note: the use of the "U" mode character is deprecated, you should specify universal-newline mode with newline=None or simply omit it, since this is the default.)
If you don't specify encoding=, then your locale is used.
To see what it is set to from within Python, try this (eg. in an interactive session):
import locale
locale.getpreferredencoding()
This tells you what is used now, which is apparently wrong.
Step 1, finding out what the correct encoding is, can be tricky.
If the source of your file doesn't tell you, then you'll have to guess.
A good guess to start with is always UTF-8, since (a) it is widespread and (b), more importantly, it is "picky": If UTF-8 is the wrong choice, then it is extremely likely that you will notice by receiving a UnicodeError.
You should try if this works.
However, if it doesn't, then it gets tricky.
Chances are that you are dealing with an 8-bit encoding, in which case you cannot rely on an exception-free pass – for example, decoding with Latin-1 will always work (you can even "decode" a JPEG image with Latin-1), but if it's the wrong choice the result is a string of gibberish.
You'll have to do some trial and error with different 8-bit encodings, and look at the problematic position to see if the result is something reasonable.

This error usually arises when you try to read a file using the wrong encoding. But given the very high offset in your case, it's also possible that you have the correct encoding but some sort of glitch in the file-- no point in speculating on the specifics.
Since the file seems to be mostly correct, I you can just ask for unhandled bytes to be replaced with the special character '�' (Unicode "\ufffd"). You can then find the context of the error by simply searching for this character.
f = open('FY16_Query_Analysis1.txt', errors="replace")
raw = f.read()
lines = raw.splitlines()
for line in lines:
if '�' in line:
print(line)
Depending on what you see, you can decide what to do next.
Alternately, you could read the file in binary mode and convert a string around the offset in question; for example:
f=open('FY16_Query_Analysis1.txt','rb')
raw = f.read()
errorpos = 16592600
fragment = raw[errorpos-20:errorpos+40]
print(repr(fragment))

Python, Hex and common file signatures

I’ve got files from a system restore which have odd bits of data padded out to the front of the file which makes it gobbledegook when opening it. I’ve got a text file of file signatures which I’ve collected, and which contain information represented like this at the moment:
Sig_MicrosoftOffice_before2007= \xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1
What I am planning on is reading the text file and using the data to identify the correct header in the data of the corrupt file, and strip everything off before it – hopefully leaving a readable file after. I’m stuck on how best to get this data into python in a readable format though.
My first try was simply reading the values from the file, but as python does, it’s representing the backslashes as the escape character. Is this the best method to achieve what I need? Do I need to think about representing the data in the text file some other way? Or maybe in a dictionary? Any help you could provide would be really appreciated.

You can decode the \xhh escapes by using the string_escape codec (Python 2) or unicode_escape codec (Python 3 or when you have to us Unicode in Python 2):
>>> r'\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1'
'\\xD0\\xCF\\x11\\xE0\\xA1\\xB1\\x1A\\xE1'
>>> r'\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1'.decode('string_escape')
'\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1'

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.. :-(

Encoding error in Python with Chinese characters

I'm a beginner having trouble decoding several dozen CSV file with numbers + (Simplified) Chinese characters to UTF-8 in Python 2.7.
I do not know the encoding of the input files so I have tried all the possible encodings I am aware of -- GB18030, UTF-7, UTF-8, UTF-16 & UTF-32 (LE & BE). Also, for good measure, GBK and GB3212, though these should be a subset of GB18030. The UTF ones all stop when they get to the first Chinese characters. The other encodings stop somewhere in the first line except GB18030. I thought this would be the solution because it read through the first few files and decoded them fine. Part of my code, reading line by line, is:
line = line.decode("GB18030")
The first 2 files I tried to decode worked fine. Midway through the third file, Python spits out
UnicodeDecodeError: 'gb18030' codec can't decode bytes in position 168-169: illegal multibyte sequence
In this file, there are about 5 such errors in about a million lines.
I opened the input file in a text editor and checked which characters were giving the decoding errors, and the first few all had Euro signs in a particular column of the CSV files. I am fairly confident these are typos, so I would just like to delete the Euro characters. I would like to examine types of encoding errors one by one; I would like to get rid of all the Euro errors but do not want to just ignore others until I look at them first.
Edit: I used chardet which gave GB2312 as the encoding with .99 confidence for all files. I tried using GB2312 to decode which gave:
UnicodeDecodeError: 'gb2312' codec can't decode bytes in position 108-109: illegal multibyte sequence

""" ... GB18030. I thought this would be the solution because it read through the first few files and decoded them fine.""" -- please explain what you mean. To me, there are TWO criteria for a successful decoding: firstly that raw_bytes.decode('some_encoding') didn't fail, secondly that the resultant unicode when displayed makes sense in a particular language. Every file in the universe will pass the first test when decoded with latin1 aka iso_8859_1. Many files in East Asian languages pass the first test with gb18030, because mostly the frequently used characters in Chinese, Japanese, and Korean are encoded using the same blocks of two-byte sequences. How much of the second test have you done?
Don't muck about looking at the data in an IDE or text editor. Look at it in a web browser; they usually make a better job of detecting encodings.
How do you know that it's a Euro character? By looking at the screen of a text editor that's decoding the raw bytes using what encoding? cp1252?
How do you know it contains Chinese characters? Are you sure it's not Japanese? Korean? Where did you get it from?
Chinese files created in Hong Kong, Taiwan, maybe Macao, and other places off the mainland use big5 or big5_hkscs encoding -- try that.
In any case, take Mark's advice and point chardet at it; chardet usually makes a reasonably good job of detecting the encoding used if the file is large enough and correctly encoded Chinese/Japanese/Korean -- however if someone has been hand editing the file in a text editor using a single-byte charset, a few illegal characters may cause the encoding used for the other 99.9% of the characters not to be detected.
You may like to do print repr(line) on say 5 lines from the file and edit the output into your question.
If the file is not confidential, you may like to make it available for download.
Was the file created on Windows? How are you reading it in Python? (show code)
Update after OP comments:
Notepad etc don't attempt to guess the encoding; "ANSI" is the default. You have to tell it what to do. What you are calling the Euro character is the raw byte "\x80" decoded by your editor using the default encoding for your environment -- the usual suspect being "cp1252". Don't use such an editor to edit your file.
Earlier you were talking about the "first few errors". Now you say you have 5 errors total. Please explain.
If the file is indeed almost correct gb18030, you should be able to decode the file line by line, and when you get such an error, trap it, print the error message, extract the byte offsets from the message, print repr(two_bad_bytes), and keep going. I'm very interested in which of the two bytes the \x80 appears. If it doesn't appear at all, the "Euro character" is not part of your problem. Note that \x80 can appear validly in a gb18030 file, but only as the 2nd byte of a 2-byte sequence starting with \x81 to \xfe.
It's a good idea to know what your problem is before you try to fix it. Trying to fix it by bashing it about with Notepad etc in "ANSI" mode is not a good idea.
You have been very coy about how you decided that the results of gb18030 decoding made sense. In particular I would be closely scrutinising the lines where gbk fails but gb18030 "works" -- there must be some extremely rare Chinese characters in there, or maybe some non-Chinese non-ASCII characters ...
Here's a suggestion for a better way to inspect the damage: decode each file with raw_bytes.decode(encoding, 'replace') and write the result (encoded in utf8) to another file. Count the errors by result.count(u'\ufffd'). View the output file with whatever you used to decide that the gb18030 decoding made sense. The U+FFFD character should show up as a white question mark inside a black diamond.
If you decide that the undecodable pieces can be discarded, the easiest way is raw_bytes.decode(encoding, 'ignore')
Update after further information
All those \\ are confusing. It appears that "getting the bytes" involves repr(repr(bytes)) instead of just repr(bytes) ... at the interactive prompt, do either bytes (you'll get an implict repr()), or print repr(bytes) (which won't get the implicit repr())
The blank space: I presume that you mean that '\xf8\xf8'.decode('gb18030') is what you interpret as some kind of full-width space, and that the interpretation is done by visual inspection using some unnameable viewer software. Is that correct?
Actually, '\xf8\xf8'.decode('gb18030') -> u'\e28b'. U+E28B is in the Unicode PUA (Private Use Area). The "blank space" presumably means that the viewer software unsuprisingly doesn't have a glyph for U+E28B in the font it is using.
Perhaps the source of the files is deliberately using the PUA for characters that are not in standard gb18030, or for annotation, or for transmitting pseudosecret info. If so, you will need to resort to the decoding tambourine, an offshoot of recent Russian research reported here.
Alternative: the cp939-HKSCS theory. According to the HK government, HKSCS big5 code FE57 was once mapped to U+E28B but is now mapped to U+28804.
The "euro": You said """Due to the data I can't share the whole line, but what I was calling the euro char is in: \xcb\xbe\x80\x80" [I'm assuming a \ was omitted from the start of that, and the " is literal]. The "euro character", when it appears, is always in the same column that I don't need, so I was hoping to just use "ignore". Unfortunately, since the "euro char" is right next to quotes in the file, sometimes "ignore" gets rid of both the euro character as well [as] quotes, which poses a problem for the csv module to determine columns"""
It would help enormously if you could show the patterns of where these \x80 bytes appear in relation to the quotes and the Chinese characters -- keep it readable by just showing the hex, and hide your confidential data e.g. by using C1 C2 to represent "two bytes which I am sure represent a Chinese character". For example:
C1 C2 C1 C2 cb be 80 80 22 # `\x22` is the quote character
Please supply examples of (1) where the " is not lost by 'replace' or 'ignore' (2) where the quote is lost. In your sole example to date, the " is not lost:
>>> '\xcb\xbe\x80\x80\x22'.decode('gb18030', 'ignore')
u'\u53f8"'
And the offer to send you some debugging code (see example output below) is still open.
>>> import decode_debug as de
>>> def logger(s):
... sys.stderr.write('*** ' + s + '\n')
...
>>> import sys
>>> de.decode_debug('\xcb\xbe\x80\x80\x22', 'gb18030', 'replace', logger)
*** input[2:5] ('\x80\x80"') doesn't start with a plausible code sequence
*** input[3:5] ('\x80"') doesn't start with a plausible code sequence
u'\u53f8\ufffd\ufffd"'
>>> de.decode_debug('\xcb\xbe\x80\x80\x22', 'gb18030', 'ignore', logger)
*** input[2:5] ('\x80\x80"') doesn't start with a plausible code sequence
*** input[3:5] ('\x80"') doesn't start with a plausible code sequence
u'\u53f8"'
>>>
Eureka: -- Probable cause of sometimes losing the quote character --
It appears there is a bug in the gb18030 decoder replace/ignore mechanism: \x80 is not a valid gb18030 lead byte; when it is detected the decoder should attempt to resync with the NEXT byte. However it seems to be ignoring both the \x80 AND the following byte:
>>> '\x80abcd'.decode('gb18030', 'replace')
u'\ufffdbcd' # the 'a' is lost
>>> de.decode_debug('\x80abcd', 'gb18030', 'replace', logger)
*** input[0:4] ('\x80abc') doesn't start with a plausible code sequence
u'\ufffdabcd'
>>> '\x80\x80abcd'.decode('gb18030', 'replace')
u'\ufffdabcd' # the second '\x80' is lost
>>> de.decode_debug('\x80\x80abcd', 'gb18030', 'replace', logger)
*** input[0:4] ('\x80\x80ab') doesn't start with a plausible code sequence
*** input[1:5] ('\x80abc') doesn't start with a plausible code sequence
u'\ufffd\ufffdabcd'
>>>

You might try chardet.

Try this:
codecs.open(file, encoding='gb18030', errors='replace')
Don't forget the parameter errors, you can also set it to 'ignore'.