How do I manually throw/raise an exception in Python?

Rajendra Dharmkar

Answered on 6th Dec, 2017

We use the most specific exception constructor that fits our specific issue rather than raise generic exceptions. To catch our specific exception, we'll have to catch all other more specific exceptions that subclass it.

We should raise specific exceptions and handle the same specific exceptions.

To raise the specific exceptions we use the raise statement as follows.

import sys
try:
f = float('Tutorialspoint')
print f
raise ValueError
except Exception as err:
print sys.exc_info()

We get following output

(<type 'exceptions.ValueError'>, ValueError('could not convert string to float: Tutorialspoint',), <traceback object at 0x0000000002E33748>)

We can raise an error even with arguments like the following example

try:
raise ValueError('foo', 23)
except ValueError, e:
print e.args

We get the following output

('foo', 23)