Get key name from Python KeyError exception

Question

I would like to get the key name from the Python KeyError exception:

For example:

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] 

i have already tried this

print e print e.args print e.message 

my code is inside django view !

if i use ipython for example and try e.arg or e.message it works fine. but then i try it while inside a django view i get this results:

"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']}> 

while i just want the 'key2'

Answer 1

You can use e.args:

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

From the docs:

The except clause may specify a variable after the exception name (or tuple). The variable is bound to an exception instance with the arguments stored in instance.args

Answer 2

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 "missing key in mydict:", e.message