CODEWITHSUNDEEP
pythondjangopython-3.xexceptionerror-handling
Joel G Mathew
Joel G Mathew

Reputation: 8061

Catch specific errors in python

I was trying to catch a specific exception:

username = 'myuser'
try:
    user = User.objects.get(username=username)
    print(user)
except Exception as e:
    if type(e)=='django.contrib.auth.models.User.DoesNotExist':
        print('No such user')

    print (type(e))

But instead of going into the if loop, I am getting:

<class 'django.contrib.auth.models.User.DoesNotExist'>

Why is this happening? How can I catch a specific exception?

Upvotes: 0

Views: 69

Answers (1)

JPG
JPG

Reputation: 88429

type(e) does not return a string. Note that

(<class 'django.contrib.auth.models.User.DoesNotExist'> != 
 'django.contrib.auth.models.User.DoesNotExist')

The if condition should be if type(e) == django.contrib.auth.models.User.DoesNotExist or better, if isinstance(e, django.contrib.auth.models.User.DoesNotExist)

However, the correct solution is to use multiple except clauses

username = 'myuser'
try:
    user = User.objects.get(username=username)
    print(user)
except User.DoesNotExist:
    # do something
    print('No such user')
except SomeOtherException:
    # do a different thing
except Foo:
    # do bar

Note that you can also combine handling of different exception types to the same except clause:

try:
    # some bad code
except (User.DoesnotExist, SomeOtherException):
    # error handling code


Reference
1. Python: One Try Multiple Except

Upvotes: 4

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