Catching Exceptions in Python

In Python, exceptions can be handled using a try statement.

A critical operation which can raise exception is placed inside the try clause and the code that handles exception is written in except clause.

It is up to us, what operations we perform once we have caught the exception. Here is a simple example.

import sys


randomList = ['a', 0, 2]


for entry in randomList:
    
try:
        
print("The entry is", entry)
        
r = 1/int(entry)
        
break
    
except:
        
print("Oops!",sys.exc_info()[0],"occured.")
        
print("Next entry.")
        
print()

print("The reciprocal of",entry,"is",r)

Catching Specific Exceptions in Python
In the above example, we did not mention any exception in the except clause.

This is not a good programming practice as it will catch all exceptions and handle every case in the same way. We can specify which exceptions an except clause will catch.

A try clause can have any number of except clause to handle them differently but only one will be executed in case an exception occurs.

We can use a tuple of values to specify multiple exceptions in an except clause. Here is an example pseudo code.

try:
   # do something
   pass

except ValueError:
   # handle ValueError exception
   pass

except (TypeError, ZeroDivisionError):
   # handle multiple exceptions
   # TypeError and ZeroDivisionError
   pass

except:
   # handle all other exceptions
   pass