Beginning Python - From Novice to Professional

570 APPENDIX B ■ PYTHON REFERENCE
The for Statement
The for statement is used for repeated execution (looping) over the elements of sequences or
other iterable objects (objects having an __iter__ method that returns an iterator). It may
include an else clause (which is executed if the loop finishes normally, without any break or
return statements, for instance).
Example:
for i in range(10, 0, -1):
print i
print 'Ignition!'
The try Statement
The try statement is used to enclose pieces of code where one or more known exceptions may
occur, and enables your program to trap these exceptions and perform exception handling
code if an exception is trapped.
Example:
try:
1/0
except ZeroDivisionError:
print "Can't divide anything by zero."
Function Definitions
Function definitions are used to create function objects and to bind global or local variables to
these function objects.
Example:
def double(x):
return x*2
Class Definitions
Class definitions are used to create class objects and to bind global or local variables to these
class objects.
Example:
class Doubler:
def __init__(self, value):
self.value = value
def double(self):
self.value *= 2