UTF-8字符串作为字典中的关键字引起KeyError [英] UTF-8 string as key in dictionary causes KeyError

问题描述

我有一个字典与unicode字符串作为键。当我尝试访问该值时，我会得到关键错误，即使字典和我的密钥中的键的打印输出相同：

 >>> test =Byggår
>>> key = raw_dict.keys（）[7] 
>>> print（test）
Byggår
>>>> print（key）
Byggår
>>> test 
'Bygg\xc3\xa5r'
>>>键
 u'Bygg\xe5r'
>>> raw_dict [test] 
追溯（最近的最后一次调用）：
文件/Applications/PyCharm.app/Contents/helpers/pydev/pydevd_exec.py，第3行，在Exec 
文件< input>，第1行，< module> 
 KeyError：'Bygg\xc3\xa5r'
  

似乎他们被编码不同，不知何故。从实验看，似乎字典中的键被编码为八进制字节（？） http://www.ltg.ed.ac.uk/~richard/utf-8.cgi?input=xc3+xa5&mode=obytes ，而我尝试访问该值的键被编码为十六进制（？） http://www.ltg.ed.ac.uk/~richard/utf-8.cgi?input=xe5&mode=hex 。

字典中的键从Web来源获取，所以我想有一些东西在路上被弄乱了。

解决方案

您的测试是一个字符串，而键是一个 unicode字符串。请参阅前面的 u

您应该使用Python 3，其中所有字符串都是Unicode字符串，或者在字典中查找之前确保将测试转换为unicode。

I have a dictionary with unicode strings as keys. When I try to access the value I get key error, even though the printout of the key in dictionary and my key are equal:

>>> test = "Byggår"
>>> key = raw_dict.keys()[7]
>>> print(test)
Byggår
>>> print(key)
Byggår
>>> test
'Bygg\xc3\xa5r'
>>> key
u'Bygg\xe5r'
>>> raw_dict[test]
Traceback (most recent call last):
  File "/Applications/PyCharm.app/Contents/helpers/pydev/pydevd_exec.py", line 3, in Exec
  File "<input>", line 1, in <module>
KeyError: 'Bygg\xc3\xa5r'

It seems as they are encoded differently, somehow. From experimenting it seems as the key in the dictionary is encoded as octal bytes (?) http://www.ltg.ed.ac.uk/~richard/utf-8.cgi?input=xc3+xa5&mode=obytes, whilst the key I try to access the value with is encoded as hex(?) http://www.ltg.ed.ac.uk/~richard/utf-8.cgi?input=xe5&mode=hex .

The keys in dictionary are fetched from a web source, so I guess something gets messed up on the way.

解决方案

Your test is a string while key is a unicode string. See the u in-front of it?

You should either use Python 3, where all strings are unicode strings, or make sure to convert test to unicode before looking for it in the dictionary.

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