UnicodeEncodeError:“ascii”编解码器无法对位置0中的字符u“\xef”进行编码：序号不在范围（128）内

Question

我想解析我的XML文档。所以我将XML文档存储如下

class XMLdocs(db.Expando):  
   id = db.IntegerProperty()    
   name=db.StringProperty()  
   content=db.BlobProperty()  

下面是我的代码

parser = make_parser()     
curHandler = BasketBallHandler()  
parser.setContentHandler(curHandler)  
for q in XMLdocs.all():  
        parser.parse(StringIO.StringIO(q.content))

我正处于错误之下

'ascii' codec can't encode character u'\xef' in position 0: ordinal not in range(128)
Traceback (most recent call last):  
  File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/__init__.py", line 517, in __call__
    handler.post(*groups)   
  File "/base/data/home/apps/parsepython/1.348669006354245654/mapreduce/base_handler.py", line 59, in post
    self.handle()   
  File "/base/data/home/apps/parsepython/1.348669006354245654/mapreduce/handlers.py", line 168, in handle
    scan_aborted = not self.process_entity(entity, ctx)   
  File "/base/data/home/apps/parsepython/1.348669006354245654/mapreduce/handlers.py", line 233, in process_entity
    handler(entity)   
  File "/base/data/home/apps/parsepython/1.348669006354245654/parseXML.py", line 71, in process
    parser.parse(StringIO.StringIO(q.content))   
  File "/base/python_runtime/python_dist/lib/python2.5/xml/sax/expatreader.py", line 107, in parse
    xmlreader.IncrementalParser.parse(self, source)   
  File "/base/python_runtime/python_dist/lib/python2.5/xml/sax/xmlreader.py", line 123, in parse
    self.feed(buffer)  
  File "/base/python_runtime/python_dist/lib/python2.5/xml/sax/expatreader.py", line 207, in feed
    self._parser.Parse(data, isFinal)   
  File "/base/data/home/apps/parsepython/1.348669006354245654/parseXML.py", line 136, in characters   
    print ch   
UnicodeEncodeError: 'ascii' codec can't encode character u'\xef' in position 0: ordinal not in range(128)   

Answer 1

似乎您遇到了一个UTF-8字节顺序标记（BOM）。尝试使用此unicode字符串提取出物料清单：

import codecs

content = unicode(q.content.strip(codecs.BOM_UTF8), 'utf-8')
parser.parse(StringIO.StringIO(content))

我使用了strip而不是lstrip，因为在您的例子中，您有多个BOM出现，可能是由于连接了文件内容。

Answer 2

这个问题的实际最佳答案取决于您的环境，特别是您的终端期望的编码。

最快的单行解决方案是将您打印的所有内容编码为ASCII（您的终端几乎肯定会接受），同时丢弃无法打印的字符：

print ch #fails
print ch.encode('ascii', 'ignore')

更好的解决方案是将终端的编码更改为utf-8，并在打印之前将所有内容编码为utf-8。每次打印或读取字符串时，您都应该养成考虑unicode编码的习惯。

Answer 3

只需将.encode('utf-8')放在对象的末尾就可以完成Python最新版本中的工作。