I am using Python 3.1 on a Windows 7 machine. Russian is the default system language, and utf-8 is the default encoding.
Looking at the answer to a previous question, I have attempting using the «codecs» module to give me a little luck. Here’s a few examples:
>>> g = codecs.open("C:UsersEricDesktopbeeline.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-4: truncated UXXXXXXXX escape (<pyshell#39>, line 1)
>>> g = codecs.open("C:UsersEricDesktopSite.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-4: truncated UXXXXXXXX escape (<pyshell#40>, line 1)
>>> g = codecs.open("C:Python31Notes.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 11-12: malformed N character escape (<pyshell#41>, line 1)
>>> g = codecs.open("C:UsersEricDesktopSite.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-4: truncated UXXXXXXXX escape (<pyshell#44>, line 1)
My last idea was, I thought it might have been the fact that Windows «translates» a few folders, such as the «users» folder, into Russian (though typing «users» is still the correct path), so I tried it in the Python31 folder. Still, no luck. Any ideas?
Introduction to Python Unicode Error
In Python, Unicode is defined as a string type for representing the characters that allow the Python program to work with any type of different possible characters. For example, any path of the directory or any link address as a string. When we use such a string as a parameter to any function, there is a possibility of the occurrence of an error. Such error is known as Unicode error in Python. We get such an error because any character after the Unicode escape sequence (“ u ”) produces an error which is a typical error on windows.
Working of Unicode Error in Python with Examples
Unicode standard in Python is the representation of characters in code point format. These standards are made to avoid ambiguity between the characters specified, which may occur Unicode errors. For example, let us consider “ I ” as roman number one. It can be even considered the capital alphabet “ i ”; they both look the same, but they are two different characters with a different meaning to avoid such ambiguity; we use Unicode standards.
In Python, Unicode standards have two types of error: Unicode encodes error and Unicode decode error. In Python, it includes the concept of Unicode error handlers. These handlers are invoked whenever a problem or error occurs in the process of encoding or decoding the string or given text. To include Unicode characters in the Python program, we first use Unicode escape symbol u before any string, which can be considered as a Unicode-type variable.
Syntax:
Unicode characters in Python program can be written as follows:
“u dfskgfkdsg”
Or
“U sakjhdxhj”
Or
“u1232hgdsa”
In the above syntax, we can see 3 different ways of declaring Unicode characters. In the Python program, we can write Unicode literals with prefix either “u” or “U” followed by a string containing alphabets and numerical where we can see the above two syntax examples. At the end last syntax sample, we can also use the “u” Unicode escape sequence to declare Unicode characters in the program. In this, we have to note that using “u”, we can write a string containing any alphabet or numerical, but when we want to declare any hex value then we have to “x” escape sequence which takes two hex digits and for octal, it will take digit 777.
Example #1
Now let us see an example below for declaring Unicode characters in the program.
Code:
#!/usr/bin/env python
# -*- coding: latin-1 -*-
a= u'dfsfxacu1234'
print("The value of the above unicode literal is as follows:")
print(ord(a[-1]))Output:
In the above program, we can see the sample of Unicode literals in the python program, but before that, we need to declare encoding, which is different in different versions of Python, and in this program, we can see in the first two lines of the program.
Now we will see the Unicode errors such as Unicode encoding Error and Unicode decoding errors, which are handled by Unicode error handlers, are invoked automatically whenever the errors are encountered. There are 3 typical errors in Python Unicode error handlers.
Strict error in Python raises UnicodeEncodeError and UnicodeDecodeError for encoding and decoding errors that are occurred, respectively.
Example #2
UnicodeEncodeError demonstration and its example.
In Python, it cannot detect Unicode characters, and therefore it throws an encoding error as it cannot encode the given Unicode string.
Code:
str(u'éducba')
Output:
In the above program, we can see we have passed the argument to the str() function, which is a Unicode string. But this function will use the default encoding process ASCII. As we can see in the above statement, we have not specified any encoding at the starting of this program, and therefore it throws an error, and the default encoding that is used is 7-bit encoding, and it cannot recognize the characters that are outside the 0 to 128 range. Therefore, we can see the error that is displayed in the above screenshot.
The above program can be fixed by encoding Unicode string manually, such as .encode(‘utf8’), before passing the Unicode string to the str() function.
Example #3
In this program, we have called the str() function explicitly, which may again throw an UnicodeEncodeError.
Code:
a = u'café'
b = a.encode('utf8')
r = str(b)
print("The unicode string after fixing the UnicodeEncodeError is as follows:")
print(r)Output:
In the above, we can show how we can avoid UnicodeEncodeError manually by using .encode(‘utf8’) to the Unicode string.
Example #4
Now we will see the UnicodeDecodeError demonstration and its example and how to avoid it.
Code:
a = u'éducba'
b = a.encode('utf8')
unicode(b)
Output:
In the above program, we can see we are trying to print the Unicode characters by encoding first; then we are trying to convert the encoded string into Unicode characters, which mean decoding back to Unicode characters as given at the starting. In the above program, when we run, we get an error as UnicodeDecodeError. So to avoid this error, we have to manually decode the Unicode character “b”.
So we can fix it by using the below statement, and we can see it in the above screenshot.
b.decode(‘utf8’)
Conclusion
In this article, we conclude that in Python, Unicode literals are other types of string for representing different types of string. In this article, we saw different errors like UnicodeEncodeError and UnicodeDecodeError, which are used to encode and decode strings in the program, along with examples. In this article, we also saw how to fix these errors manually by passing the string to the function.
Recommended Articles
This is a guide to Python Unicode Error. Here we discuss the introduction to Python Unicode Error and working of Unicode error with examples, respectively. You may also have a look at the following articles to learn more –
- Python String Operations
- Python Sort List
- Quick Sort in Python
- Python Constants
The original answers should work.
Option 1:
file_path = "c:\User\USER\SOMETHINGELSE"
print(file_path);
gives:
c:UserUSERSOMETHINGELSE
The slash escapes the character next to it, but doesn’t print itself.
Option 2:
file_path = r"c:UserUSERSOMETHINGELSE"
print(file_path);
gives:
c:UserUSERSOMETHINGELSE
The r tells the string that it has to take it as literal and not use any escape characters.
Option 3:
OK…So if you really can’t use options 1 or 2, you could use:
import os
file_path = os.path.join(os.path.abspath(os.sep), 'Users', 'USER', 'SOMETHINGELSE')
print(file_path);
In this case ‘os.path.abspath(os.sep)’ returns the root drive you are currently using. In my case C:.
‘os.path.join’ concatenates the strings using the current systems delimiter. On windows this is .
The result is:
C:UsersUSERSOMETHINGELSE
But, that is a strange way of doing things when option 1 or 2 should work fine.
Remember not to use the options together. If you combine options 1 and 2 you will not get the correct result. Use one or the other.
The original answers should work.
Option 1:
file_path = "c:\User\USER\SOMETHINGELSE"
print(file_path);
gives:
c:UserUSERSOMETHINGELSE
The slash escapes the character next to it, but doesn’t print itself.
Option 2:
file_path = r"c:UserUSERSOMETHINGELSE"
print(file_path);
gives:
c:UserUSERSOMETHINGELSE
The r tells the string that it has to take it as literal and not use any escape characters.
Option 3:
OK…So if you really can’t use options 1 or 2, you could use:
import os
file_path = os.path.join(os.path.abspath(os.sep), 'Users', 'USER', 'SOMETHINGELSE')
print(file_path);
In this case ‘os.path.abspath(os.sep)’ returns the root drive you are currently using. In my case C:.
‘os.path.join’ concatenates the strings using the current systems delimiter. On windows this is .
The result is:
C:UsersUSERSOMETHINGELSE
But, that is a strange way of doing things when option 1 or 2 should work fine.
Remember not to use the options together. If you combine options 1 and 2 you will not get the correct result. Use one or the other.
Table of Contents
Hide
- What is SyntaxError: (unicode error) ‘unicodeescape’ codec can’t decode bytes in position 2-3: truncated UXXXXXXXX escape?
- How to fix SyntaxError: (unicode error) ‘unicodeescape’ codec can’t decode bytes in position 2-3: truncated UXXXXXXXX escape?
- Solution 1 – Using Double backslash (\)
- Solution 2 – Using raw string by prefixing ‘r’
- Solution 3 – Using forward slash
- Conclusion
The SyntaxError: (unicode error) ‘unicodeescape’ codec can’t decode bytes in position 2-3: truncated UXXXXXXXX escape occurs if you are trying to access a file path with a regular string.
In this tutorial, we will take a look at what exactly (unicode error) ‘unicodeescape’ codec can’t decode bytes in position 2-3: truncated UXXXXXXXX escape means and how to fix it with examples.
The Python String literals can be enclosed in matching single quotes (‘) or double quotes (“).
String literals can also be prefixed with a letter ‘r‘ or ‘R‘; such strings are called raw strings and use different rules for backslash escape sequences.
They can also be enclosed in matching groups of three single or double quotes (these are generally referred to as triple-quoted strings).
The backslash () character is used to escape characters that otherwise have a special meaning, such as newline, backslash itself, or the quote character.
Now that we have understood the string literals. Let us take an example to demonstrate the issue.
import pandas
# read the file
pandas.read_csv("C:UsersitsmycodeDesktoptest.csv")
Output
File "c:PersonalIJSCodeprogram.py", line 4
pandas.read_csv("C:UsersitsmycodeDesktoptest.csv") ^
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated UXXXXXXXX escapeWe are using the single backslash in the above code while providing the file path. Since the backslash is present in the file path, it is interpreted as a special character or escape character (any sequence starting with ‘’). In particular, “U” introduces a 32-bit Unicode character.
How to fix SyntaxError: (unicode error) ‘unicodeescape’ codec can’t decode bytes in position 2-3: truncated UXXXXXXXX escape?
Solution 1 – Using Double backslash (\)
In Python, the single backslash in the string is interpreted as a special character, and the character U(in users) will be treated as the Unicode code point.
We can fix the issue by escaping the backslash, and we can do that by adding an additional backslash, as shown below.
import pandas
# read the file
pandas.read_csv("C:\Users\itsmycode\Desktop\test.csv")Solution 2 – Using raw string by prefixing ‘r’
We can also escape the Unicode by prefixing r in front of the string. The r stands for “raw” and indicates that backslashes need to be escaped, and they should be treated as a regular backslash.
import pandas
# read the file
pandas.read_csv("C:\Users\itsmycode\Desktop\test.csv")Solution 3 – Using forward slash
Another easier way is to avoid the backslash and instead replace it with the forward-slash character(/), as shown below.
import pandas
# read the file
pandas.read_csv("C:/Users/itsmycode/Desktop/test.csv")
Conclusion
The SyntaxError: (unicode error) ‘unicodeescape’ codec can’t decode bytes in position 2-3: truncated UXXXXXXXX escape occurs if you are trying to access a file path and provide the path as a regular string.
We can solve the issue by escaping the single backslash with a double backslash or prefixing the string with ‘r,’ which converts it into a raw string. Alternatively, we can replace the backslash with a forward slash.
Srinivas Ramakrishna is a Solution Architect and has 14+ Years of Experience in the Software Industry. He has published many articles on Medium, Hackernoon, dev.to and solved many problems in StackOverflow. He has core expertise in various technologies such as Microsoft .NET Core, Python, Node.JS, JavaScript, Cloud (Azure), RDBMS (MSSQL), React, Powershell, etc.
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PEP: Python3 and UnicodeDecodeError
This is a PEP describing the behaviour of Python3 on UnicodeDecodeError. It’s a draft, don’t hesitate to comment it. This document suppose that my patch to allow bytes filenames is accepted which is not the case today.
While I was writing this document I found poential problems in Python3. So here is a TODO list (things to be checked):
- FIXME: When bytearray is accepted or not?
- FIXME: Allow bytes/str mix for shutil.copy*()? The ignore callback will get bytes or unicode?
Can anyone write a section about bytes encoding in Unicode using escape sequence?
What is the best tool to work on a PEP? I hate email threads, and I would prefer SVN / Mercurial / anything else.
Python3 and UnicodeDecodeError for the command line, environment variables and filenames
Introduction
Python3 does its best to give you texts encoded as a valid unicode characters strings. When it hits an invalid bytes sequence (according to the used charset), it has two choices: drops the value or raises an UnicodeDecodeError. This document present the behaviour of Python3 for the command line, environment variables and filenames.
Example of an invalid bytes sequence: ::
>>> str(b'xff', 'utf8') UnicodeDecodeError: 'utf8' codec can't decode byte 0xff (...)
whereas the same byte sequence is valid in another charset like ISO-8859-1: ::
>>> str(b'xff', 'iso-8859-1') 'ÿ'
Default encoding
Python uses «UTF-8» as the default Unicode encoding. You can read the default charset using sys.getdefaultencoding(). The «default encoding» is used by PyUnicode_FromStringAndSize().
A function sys.setdefaultencoding() exists, but it raises a ValueError for charset different than UTF-8 since the charset is hardcoded in PyUnicode_FromStringAndSize().
Command line
Python creates a nice unicode table for sys.argv using mbstowcs(): ::
$ ./python -c 'import sys; print(sys.argv)' 'Ho hé !' ['-c', 'Ho hé !']
On Linux, mbstowcs() uses LC_CTYPE environement variable to choose the encoding. On an invalid bytes sequence, Python quits directly with an exit code 1. Example with UTF-8 locale:
$ python3.0 $(echo -e 'invalid:xff') Could not convert argument 1 to string
Environment variables
Python uses «_wenviron» on Windows which are contains unicode (UTF-16-LE) strings. On other OS, it uses «environ» variable and the UTF-8 charset. It drops a variable if its key or value is not convertible to unicode. Example:
env -i HOME=/home/my PATH=$(echo -e "xff") python
>>> import os; list(os.environ.items())
[('HOME', '/home/my')]
Both key and values are unicode strings. Empty key and/or value are allowed.
Python ignores invalid variables, but values still exist in memory. If you run a child process (eg. using os.system()), the «invalid» variables will also be copied.
Filenames
Introduction
Python2 uses byte filenames everywhere, but it was also possible to use unicode filenames. Examples:
- os.getcwd() gives bytes whereas os.getcwdu() always returns unicode
-
os.listdir(unicode) creates bytes or unicode filenames (fallback to bytes on UnicodeDecodeError), os.readlink() has the same behaviour
- glob.glob() converts the unicode pattern to bytes, and so create bytes filenames
- open() supports bytes and unicode
Since listdir() mix bytes and unicode, you are not able to manipulate easily filenames:
>>> path=u'.'
>>> for name in os.listdir(path):
... print repr(name)
... print repr(os.path.join(path, name))
...
u'valid'
u'./valid'
'invalidxff'
Traceback (most recent call last):
...
File "/usr/lib/python2.5/posixpath.py", line 65, in join
path += '/' + b
UnicodeDecodeError: 'ascii' codec can't decode byte 0xff (...)
Python3 supports both types, bytes and unicode, but disallow mixing them. If you ask for unicode, you will always get unicode or an exception is raised.
You should only use unicode filenames, except if you are writing a program fixing file system encoding, a backup tool or you users are unable to fix their broken system.
Windows
Microsoft Windows since Windows 95 only uses Unicode (UTF-16-LE) filenames. So you should only use unicode filenames.
Non Windows (POSIX)
POSIX OS like Linux uses bytes for historical reasons. In the best case, all filenames will be encoded as valid UTF-8 strings and Python creates valid unicode strings. But since system calls uses bytes, the file system may returns an invalid filename, or a program can creates a file with an invalid filename.
An invalid filename is a string which can not be decoded to unicode using the default file system encoding (which is UTF-8 most of the time).
A robust program will have to use only the bytes type to make sure that it can open / copy / remove any file or directory.
Filename encoding
Python use:
- «mbcs» on Windows
- or «utf-8» on Mac OS X
- or nl_langinfo(CODESET) on OS supporting this function
- or UTF-8 by default
«mbcs» is not a valid charset name, it’s an internal charset saying that Python will use the function MultiByteToWideChar() to decode bytes to unicode. This function uses the current codepage to decode bytes string.
You can read the charset using sys.getfilesystemencoding(). The function may returns None if Python is unable to determine the default encoding.
PyUnicode_DecodeFSDefaultAndSize() uses the default file system encoding, or UTF-8 if it is not set.
On UNIX (and other operating systems), it’s possible to mount different file systems using different charsets. sys.getdefaultencoding() will be the same for the different file systems since this encoding is only used between Python and the Linux kernel, not between the kernel and the file system which may uses a different charset.
Display a filename
Example of a function formatting a filename to display it to human eyes: ::
from sys import getfilesystemencoding
def format_filename(filename):
return str(filename, getfilesystemencoding(), 'replace')
Example: format_filename(‘rxffport.doc’) gives ‘r�port.doc’ with the UTF-8 encoding.
Functions producing filenames
Policy: for unicode arguments: drop invalid bytes filenames; for bytes arguments: return bytes
- os.listdir()
- glob.glob()
This behaviour (drop silently invalid filenames) is motivated by the fact to if a directory of 1000 files only contains one invalid file, listdir() fails for the whole directory. Or if your directory contains 1000 python scripts (.py) and just one another document with an invalid filename (eg. r�port.doc), glob.glob(‘*.py’) fails whereas all .py scripts have valid filename.
Policy: for an unicode argument: raise an UnicodeDecodeError on invalid filename; for an bytes argument: return bytes
- os.readlink()
Policy: create unicode directory or raise an UnicodeDecodeError
- os.getcwd()
Policy: always returns bytes
- os.getcwdb()
Functions for filename manipulation
Policy: raise TypeError on bytes/str mix
- os.path.*(), eg. os.path.join()
- fnmatch.*()
Functions accessing files
Policy: accept both bytes and str
- io.open()
- os.open()
- os.chdir()
- os.stat(), os.lstat()
- os.rename()
- os.unlink()
- shutil.*()
os.rename(), shutil.copy*(), shutil.move() allow to use bytes for an argment, and unicode for the other argument
bytearray
In most cases, bytearray() can be used as bytes for a filename.
Unicode normalisation
Unicode characters can be normalized in 4 forms: NFC, NFD, NFKC or NFKD. Python does never normalize strings (nor filenames). No operating system does normalize filenames. So the users using different norms will be unable to retrieve their file. Don’t panic! All users use the same norm.
Use unicodedata.normalize() to normalize an unicode string.