EXCEPTION HANDLING IN PYTHON

Unlike JavaScript you cannot add a number and a string in Python. However, you can detect an illegal operation using the try/except construct in Python, which is similar to the try/catch construct in languages such as JavaScript and Java.

An example of a try/except block is here:

try:
  x = 4
  y = 'abc'
  z = x + y
except:
  print 'cannot add incompatible types:', x, y

When you run the preceding code in Python, the print statement in the except code block is executed because the variables x and y have incompatible types.

Earlier in the appendix you also saw that subtracting two strings throws an exception:

>>> 'a' - 'b'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for -: 'str' and 'str'

A simple way to handle this situation is to use a try/except block:

>>> try:
...  print('a' -...