最近在用Python处理中文字符串时，报出了如下错误：
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe9 in position 0: ordinal not in range(128)
1、原因
因为默认情况下，Python采用的是ascii编码方式，如下所示：
◄► python -c "import sys; print sys.getdefaultencoding()"
ascii
◄►
而Python在进行编码方式之间的转换时，会将 unicode 作为“中间编码”，但 unicode 最大只有 128 那么长，所以这里当尝试将 ascii 编码字符串转换成"中间编码" unicode 时由于超出了其范围，就报出了如上错误。
2、解决办法
1）第一种：这里我们将Python的默认编码方式修改为utf-8，就可以规避上述问题的发生，具体方式，我们在Python文件的前面加上如下代码：
import sys
defaultencoding = 'utf-8'
if sys.getdefaultencoding() != defaultencoding:
reload(sys)
sys.setdefaultencoding(defaultencoding)
2）第二种：我们在/usr/lib/python2.7/site-packages/目录下添加一个sitecustomize.py文件，内容如下：
import sys
sys.setdefaultencoding('utf-8')
这种方式可以解决所有项目的encoding问题，具体说明可参考/usr/lib/python2.7/site.py文件：
"""Append module search paths for third-party packages to sys.path. ****************************************************************
* This module is automatically imported during initialization. *
**************************************************************** In earlier versions of Python (up to 1.5a3), scripts or modules that
needed to use site-specific modules would place ``import site''
somewhere near the top of their code. Because of the automatic
import, this is no longer necessary (but code that does it still
works). This will append site-specific paths to the module search path. On
Unix (including Mac OSX), it starts with sys.prefix and
sys.exec_prefix (if different) and appends
lib/python<version>/site-packages as well as lib/site-python.
On other platforms (such as Windows), it tries each of the
prefixes directly, as well as with lib/site-packages appended. The
resulting directories, if they exist, are appended to sys.path, and
also inspected for path configuration files. For Debian and derivatives, this sys.path is augmented with directories
for packages distributed within the distribution. Local addons go
into /usr/local/lib/python<version>/dist-packages, Debian addons
install into /usr/{lib,share}/python<version>/dist-packages.
/usr/lib/python<version>/site-packages is not used. A path configuration file is a file whose name has the form
<package>.pth; its contents are additional directories (one per line)
to be added to sys.path. Non-existing directories (or
non-directories) are never added to sys.path; no directory is added to
sys.path more than once. Blank lines and lines beginning with
'#' are skipped. Lines starting with 'import' are executed. For example, suppose sys.prefix and sys.exec_prefix are set to
/usr/local and there is a directory /usr/local/lib/python2.5/site-packages
with three subdirectories, foo, bar and spam, and two path
configuration files, foo.pth and bar.pth. Assume foo.pth contains the
following: # foo package configuration
foo
bar
bletch and bar.pth contains: # bar package configuration
bar Then the following directories are added to sys.path, in this order: /usr/local/lib/python2.5/site-packages/bar
/usr/local/lib/python2.5/site-packages/foo Note that bletch is omitted because it doesn't exist; bar precedes foo
because bar.pth comes alphabetically before foo.pth; and spam is
omitted because it is not mentioned in either path configuration file. After these path manipulations, an attempt is made to import a module
named sitecustomize, which can perform arbitrary additional
site-specific customizations. If this import fails with an
ImportError exception, it is silently ignored. """ import sys
import os
import __builtin__
import traceback # Prefixes for site-packages; add additional prefixes like /usr/local here
PREFIXES = [sys.prefix, sys.exec_prefix]
# Enable per user site-packages directory
# set it to False to disable the feature or True to force the feature
ENABLE_USER_SITE = None # for distutils.commands.install
# These values are initialized by the getuserbase() and getusersitepackages()
# functions, through the main() function when Python starts.
USER_SITE = None
USER_BASE = None def makepath(*paths):
dir = os.path.join(*paths)
try:
dir = os.path.abspath(dir)
except OSError:
pass
return dir, os.path.normcase(dir) def abs__file__():
"""Set all module' __file__ attribute to an absolute path"""
for m in sys.modules.values():
if hasattr(m, '__loader__'):
continue # don't mess with a PEP 302-supplied __file__
try:
m.__file__ = os.path.abspath(m.__file__)
except (AttributeError, OSError):
pass def removeduppaths():
""" Remove duplicate entries from sys.path along with making them
absolute"""
# This ensures that the initial path provided by the interpreter contains
# only absolute pathnames, even if we're running from the build directory.
L = []
known_paths = set()
for dir in sys.path:
# Filter out duplicate paths (on case-insensitive file systems also
# if they only differ in case); turn relative paths into absolute
# paths.
dir, dircase = makepath(dir)
if not dircase in known_paths:
L.append(dir)
known_paths.add(dircase)
sys.path[:] = L
return known_paths def _init_pathinfo():
"""Return a set containing all existing directory entries from sys.path"""
d = set()
for dir in sys.path:
try:
if os.path.isdir(dir):
dir, dircase = makepath(dir)
d.add(dircase)
except TypeError:
continue
return d def addpackage(sitedir, name, known_paths):
"""Process a .pth file within the site-packages directory:
For each line in the file, either combine it with sitedir to a path
and add that to known_paths, or execute it if it starts with 'import '.
"""
if known_paths is None:
_init_pathinfo()
reset = 1
else:
reset = 0
fullname = os.path.join(sitedir, name)
try:
f = open(fullname, "rU")
except IOError:
return
with f:
for n, line in enumerate(f):
if line.startswith("#"):
continue
try:
if line.startswith(("import ", "import\t")):
exec line
continue
line = line.rstrip()
dir, dircase = makepath(sitedir, line)
if not dircase in known_paths and os.path.exists(dir):
sys.path.append(dir)
known_paths.add(dircase)
except Exception as err:
print >>sys.stderr, "Error processing line {:d} of {}:\n".format(
n+1, fullname)
for record in traceback.format_exception(*sys.exc_info()):
for line in record.splitlines():
print >>sys.stderr, ' '+line
print >>sys.stderr, "\nRemainder of file ignored"
break
if reset:
known_paths = None
return known_paths def addsitedir(sitedir, known_paths=None):
"""Add 'sitedir' argument to sys.path if missing and handle .pth files in
'sitedir'"""
if known_paths is None:
known_paths = _init_pathinfo()
reset = 1
else:
reset = 0
sitedir, sitedircase = makepath(sitedir)
if not sitedircase in known_paths:
sys.path.append(sitedir) # Add path component
try:
names = os.listdir(sitedir)
except os.error:
return
dotpth = os.extsep + "pth"
names = [name for name in names if name.endswith(dotpth)]
for name in sorted(names):
addpackage(sitedir, name, known_paths)
if reset:
known_paths = None
return known_paths def check_enableusersite():
"""Check if user site directory is safe for inclusion The function tests for the command line flag (including environment var),
process uid/gid equal to effective uid/gid. None: Disabled for security reasons
False: Disabled by user (command line option)
True: Safe and enabled
"""
if sys.flags.no_user_site:
return False if hasattr(os, "getuid") and hasattr(os, "geteuid"):
# check process uid == effective uid
if os.geteuid() != os.getuid():
return None
if hasattr(os, "getgid") and hasattr(os, "getegid"):
# check process gid == effective gid
if os.getegid() != os.getgid():
return None return True def getuserbase():
"""Returns the `user base` directory path. The `user base` directory can be used to store data. If the global
variable ``USER_BASE`` is not initialized yet, this function will also set
it.
"""
global USER_BASE
if USER_BASE is not None:
return USER_BASE
from sysconfig import get_config_var
USER_BASE = get_config_var('userbase')
return USER_BASE def getusersitepackages():
"""Returns the user-specific site-packages directory path. If the global variable ``USER_SITE`` is not initialized yet, this
function will also set it.
"""
global USER_SITE
user_base = getuserbase() # this will also set USER_BASE if USER_SITE is not None:
return USER_SITE from sysconfig import get_path
import os if sys.platform == 'darwin':
from sysconfig import get_config_var
if get_config_var('PYTHONFRAMEWORK'):
USER_SITE = get_path('purelib', 'osx_framework_user')
return USER_SITE USER_SITE = get_path('purelib', '%s_user' % os.name)
return USER_SITE def addusersitepackages(known_paths):
"""Add a per user site-package to sys.path Each user has its own python directory with site-packages in the
home directory.
"""
# get the per user site-package path
# this call will also make sure USER_BASE and USER_SITE are set
user_site = getusersitepackages() if ENABLE_USER_SITE and os.path.isdir(user_site):
addsitedir(user_site, known_paths)
if ENABLE_USER_SITE:
for dist_libdir in ("local/lib", "lib"):
user_site = os.path.join(USER_BASE, dist_libdir,
"python" + sys.version[:3],
"dist-packages")
if os.path.isdir(user_site):
addsitedir(user_site, known_paths)
return known_paths def getsitepackages():
"""Returns a list containing all global site-packages directories
(and possibly site-python). For each directory present in the global ``PREFIXES``, this function
will find its `site-packages` subdirectory depending on the system
environment, and will return a list of full paths.
"""
sitepackages = []
seen = set() for prefix in PREFIXES:
if not prefix or prefix in seen:
continue
seen.add(prefix) if sys.platform in ('os2emx', 'riscos'):
sitepackages.append(os.path.join(prefix, "Lib", "site-packages"))
elif os.sep == '/':
sitepackages.append(os.path.join(prefix, "local/lib",
"python" + sys.version[:3],
"dist-packages"))
sitepackages.append(os.path.join(prefix, "lib",
"python" + sys.version[:3],
"dist-packages"))
else:
sitepackages.append(prefix)
sitepackages.append(os.path.join(prefix, "lib", "site-packages"))
if sys.platform == "darwin":
# for framework builds *only* we add the standard Apple
# locations.
from sysconfig import get_config_var
framework = get_config_var("PYTHONFRAMEWORK")
if framework:
sitepackages.append(
os.path.join("/Library", framework,
sys.version[:3], "site-packages"))
return sitepackages def addsitepackages(known_paths):
"""Add site-packages (and possibly site-python) to sys.path"""
for sitedir in getsitepackages():
if os.path.isdir(sitedir):
addsitedir(sitedir, known_paths) return known_paths def setBEGINLIBPATH():
"""The OS/2 EMX port has optional extension modules that do double duty
as DLLs (and must use the .DLL file extension) for other extensions.
The library search path needs to be amended so these will be found
during module import. Use BEGINLIBPATH so that these are at the start
of the library search path. """
dllpath = os.path.join(sys.prefix, "Lib", "lib-dynload")
libpath = os.environ['BEGINLIBPATH'].split(';')
if libpath[-1]:
libpath.append(dllpath)
else:
libpath[-1] = dllpath
os.environ['BEGINLIBPATH'] = ';'.join(libpath) def setquit():
"""Define new builtins 'quit' and 'exit'. These are objects which make the interpreter exit when called.
The repr of each object contains a hint at how it works. """
if os.sep == ':':
eof = 'Cmd-Q'
elif os.sep == '\\':
eof = 'Ctrl-Z plus Return'
else:
eof = 'Ctrl-D (i.e. EOF)' class Quitter(object):
def __init__(self, name):
self.name = name
def __repr__(self):
return 'Use %s() or %s to exit' % (self.name, eof)
def __call__(self, code=None):
# Shells like IDLE catch the SystemExit, but listen when their
# stdin wrapper is closed.
try:
sys.stdin.close()
except:
pass
raise SystemExit(code)
__builtin__.quit = Quitter('quit')
__builtin__.exit = Quitter('exit') class _Printer(object):
"""interactive prompt objects for printing the license text, a list of
contributors and the copyright notice.""" MAXLINES = 23 def __init__(self, name, data, files=(), dirs=()):
self.__name = name
self.__data = data
self.__files = files
self.__dirs = dirs
self.__lines = None def __setup(self):
if self.__lines:
return
data = None
for dir in self.__dirs:
for filename in self.__files:
filename = os.path.join(dir, filename)
try:
fp = file(filename, "rU")
data = fp.read()
fp.close()
break
except IOError:
pass
if data:
break
if not data:
data = self.__data
self.__lines = data.split('\n')
self.__linecnt = len(self.__lines) def __repr__(self):
self.__setup()
if len(self.__lines) <= self.MAXLINES:
return "\n".join(self.__lines)
else:
return "Type %s() to see the full %s text" % ((self.__name,)*2) def __call__(self):
self.__setup()
prompt = 'Hit Return for more, or q (and Return) to quit: '
lineno = 0
while 1:
try:
for i in range(lineno, lineno + self.MAXLINES):
print self.__lines[i]
except IndexError:
break
else:
lineno += self.MAXLINES
key = None
while key is None:
key = raw_input(prompt)
if key not in ('', 'q'):
key = None
if key == 'q':
break def setcopyright():
"""Set 'copyright' and 'credits' in __builtin__"""
__builtin__.copyright = _Printer("copyright", sys.copyright)
if sys.platform[:4] == 'java':
__builtin__.credits = _Printer(
"credits",
"Jython is maintained by the Jython developers (www.jython.org).")
else:
__builtin__.credits = _Printer("credits", """\
Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
for supporting Python development. See www.python.org for more information.""")
here = os.path.dirname(os.__file__)
__builtin__.license = _Printer(
"license", "See https://www.python.org/psf/license/",
["LICENSE.txt", "LICENSE"],
[os.path.join(here, os.pardir), here, os.curdir]) class _Helper(object):
"""Define the builtin 'help'.
This is a wrapper around pydoc.help (with a twist). """ def __repr__(self):
return "Type help() for interactive help, " \
"or help(object) for help about object."
def __call__(self, *args, **kwds):
import pydoc
return pydoc.help(*args, **kwds) def sethelper():
__builtin__.help = _Helper() def aliasmbcs():
"""On Windows, some default encodings are not provided by Python,
while they are always available as "mbcs" in each locale. Make
them usable by aliasing to "mbcs" in such a case."""
if sys.platform == 'win32':
import locale, codecs
enc = locale.getdefaultlocale()[1]
if enc.startswith('cp'): # "cp***" ?
try:
codecs.lookup(enc)
except LookupError:
import encodings
encodings._cache[enc] = encodings._unknown
encodings.aliases.aliases[enc] = 'mbcs' def setencoding():
"""Set the string encoding used by the Unicode implementation. The
default is 'ascii', but if you're willing to experiment, you can
change this."""
encoding = "ascii" # Default value set by _PyUnicode_Init()
if 0:
# Enable to support locale aware default string encodings.
import locale
loc = locale.getdefaultlocale()
if loc[1]:
encoding = loc[1]
if 0:
# Enable to switch off string to Unicode coercion and implicit
# Unicode to string conversion.
encoding = "undefined"
if encoding != "ascii":
# On Non-Unicode builds this will raise an AttributeError...
sys.setdefaultencoding(encoding) # Needs Python Unicode build ! def execsitecustomize():
"""Run custom site specific code, if available."""
try:
import sitecustomize
except ImportError:
pass
except Exception:
if sys.flags.verbose:
sys.excepthook(*sys.exc_info())
else:
print >>sys.stderr, \
"'import sitecustomize' failed; use -v for traceback" def execusercustomize():
"""Run custom user specific code, if available."""
try:
import usercustomize
except ImportError:
pass
except Exception:
if sys.flags.verbose:
sys.excepthook(*sys.exc_info())
else:
print>>sys.stderr, \
"'import usercustomize' failed; use -v for traceback" def main():
global ENABLE_USER_SITE abs__file__()
known_paths = removeduppaths()
if ENABLE_USER_SITE is None:
ENABLE_USER_SITE = check_enableusersite()
known_paths = addusersitepackages(known_paths)
known_paths = addsitepackages(known_paths)
if sys.platform == 'os2emx':
setBEGINLIBPATH()
setquit()
setcopyright()
sethelper()
aliasmbcs()
setencoding()
execsitecustomize()
if ENABLE_USER_SITE:
execusercustomize()
# Remove sys.setdefaultencoding() so that users cannot change the
# encoding after initialization. The test for presence is needed when
# this module is run as a script, because this code is executed twice.
if hasattr(sys, "setdefaultencoding"):
del sys.setdefaultencoding main() def _script():
help = """\
%s [--user-base] [--user-site] Without arguments print some useful information
With arguments print the value of USER_BASE and/or USER_SITE separated
by '%s'. Exit codes with --user-base or --user-site:
0 - user site directory is enabled
1 - user site directory is disabled by user
2 - uses site directory is disabled by super user
or for security reasons
>2 - unknown error
"""
args = sys.argv[1:]
if not args:
print "sys.path = ["
for dir in sys.path:
print " %r," % (dir,)
print "]"
print "USER_BASE: %r (%s)" % (USER_BASE,
"exists" if os.path.isdir(USER_BASE) else "doesn't exist")
print "USER_SITE: %r (%s)" % (USER_SITE,
"exists" if os.path.isdir(USER_SITE) else "doesn't exist")
print "ENABLE_USER_SITE: %r" % ENABLE_USER_SITE
sys.exit(0) buffer = []
if '--user-base' in args:
buffer.append(USER_BASE)
if '--user-site' in args:
buffer.append(USER_SITE) if buffer:
print os.pathsep.join(buffer)
if ENABLE_USER_SITE:
sys.exit(0)
elif ENABLE_USER_SITE is False:
sys.exit(1)
elif ENABLE_USER_SITE is None:
sys.exit(2)
else:
sys.exit(3)
else:
import textwrap
print textwrap.dedent(help % (sys.argv[0], os.pathsep))
sys.exit(10) if __name__ == '__main__':
_script()