从Python KeyError异常中获取密钥名称

Question

我想从Python KeyError异常中获取密钥名称:

例如:

myDict = {'key1':'value1'}
try:
    x1 = myDict['key1']
    x2 = myDict['key2'] 
except KeyError as e:
    # here i want to use the name of the key that was missing which is 'key2' in this example
    print error_msg[missing_key]

我已经试过了

print e
print e.args
print e.message

我的代码在django视图里面!

如果我使用ipython作为例子并尝试e.arg或e.message它工作正常.但后来我在django视图中尝试它,我得到这个结果:

"Key 'key2' not found in <QueryDict: {u'key1': [u'value']}>" 
("Key 'key2' not found in <QueryDict: {u'key1': [u'value']}>",) 
Key 'key2' not found in <QueryDict: {u'key1': [u'value']}>

虽然我只想要'key2'

Answer 1

你可以使用e.args:

[53]: try:
    x2 = myDict['key2']
except KeyError as e:    
    print e.args[0]
   ....:     
key2

来自文档:

except子句可以在异常名称(或元组)之后指定变量.变量绑定到存储参数的异常实例instance.args

Answer 2

由于您的字典实际上是 a QueryDict，因此返回不同的错误消息，因此您需要解析异常消息以返回单引号中的第一个单词：

import re
#...
except KeyError as e:
    m = re.search("'([^']*)'", e.message)
    key = m.group(1)