Python allows you to create an exception handler to detect a runtime error and keep it from terminating your program. To create an exception handler, use the try and except statements.

Here is a simple example of a program that uses an exception handler to catch a division by zero error:

totalcost = 4000
days = 0
try:
    cost = totalcost / days
    print "The result is", cost
except ZeroDivisionError:
    print "Division by zero error detected: division not performed"
print "This statement is outside the exception handler"

In this example, the try statement specifies the code that might contain the division by zero error, and the except statement specifies the code that is executed if the error is detected. Indenting indicates which statements are enclosed by try and except.

If you run this example program, its output looks like this:

Division by zero error detected: division not performed
This statement is outside the exception handler

Here is what is happening:

• When the program reaches the exception handler, it first tries to execute the statements contained inside the try statement.
• When it detects the attempt to divide by zero, it stops executing the code inside the try statement, and jumps to the statements inside the except statement.
• It then continues with the code immediately following the exception handler.

This exception handler protects the example program from division by zero errors. The program does not terminate if this error is detected.

	The error name used in the except statement always matches the error name that appears in its related error message. For example, here is a typical division by zero error message: Traceback (most recent call last): File "C:\Documents and Settings\Administrator\My Documents\test.py", line 3, in ? cost = totalcost /days ZeroDivisionError: integer division or modulo by zero In this error, the error name is ZeroDivisionError. This is the name that must appear in any except statement that catches division by zero errors.