21_exceptionsExample.py

#!/usr/bin/env python3

"""
Exceptions in Python

How to deal with errors / exceptions like "File not found", "division by zero",
"conversion not possible" etc. in Python and prevent that your program crashes
for example by wrong formatted input files etc.

https://wiki.python.org/moin/HandlingExceptions

Jens Dede, 2019, jd@comnets.uni-bremen.de
"""

print(5*"*", "Catch a specific error")
try:
    print(1/0)   # Division by zero not possible -> Exception
except ZeroDivisionError:   # Will catch the ZeroDivisionErrors
    print("Division by Zero catched")
    # Do whatever is necessary to solve the exception

print(5*"*", "Catch a general error")
try:
    print(2/0)   # Again an exception
except:
    print("Something went wrong...")

print(5*"*", "Catch a general error with some more information")
try:
    print(3/0)   # Again an exception
except Exception as e:
    print("Something went wrong and I have the following information:")
    print(e)

# The following line will show what happens if an error is not caught:
# Program will crash...
a = 5/"b"

# ... and the following print will never be executed
print("You will never see this message")