Python suggest change

Raise Custom Errors Exceptions

Python has many built-in exceptions which force your program to output an error when something in it goes wrong.

However, sometimes you may need to create custom exceptions that serve your purpose.

In Python, users can define such exceptions by creating a new class. This exception class has to be derived, either directly or indirectly, from Exception class. Most of the built-in exceptions are also derived from this class.

Custom Exception

Here, we have created a user-defined exception called CustomError which is derived from the Exception class. This new exception can be raised, like other exceptions, using the raise statement with an optional error message.

class CustomError(Exception):

x = 1

if x == 1:
    raise CustomError('This is custom error')


Traceback (most recent call last):
  File "", line 8, in <module>
    raise CustomError('This is custom error')
__main__.CustomError: This is custom error

Catch custom Exception

This example shows how to catch custom Exception

class CustomError(Exception):

raise CustomError('Can you catch me ?')
except CustomError as e:
print ('Catched CustomError :{}'.format(e))
except Exception as e:
print ('Generic exception: {}'.format(e))


Catched CustomError :Can you catch me ?

Feedback about page:

Optional: your email if you want me to get back to you:

Table Of Contents
32 Set
46 Enum
105 Stack
119 Mixins
121 ArcPy
127 Arrays
139 Neo4j
141 Curses
146 heapq
155 Audio
156 pyglet
158 ijson
161 Flask
164 pygame
167 Gzip
168 ctypes
187 shelve
190 Raise Custom Errors Exceptions
  ↑ ↓ to navigate     ↵ to select     Esc to close