Iterator
class custom_iterator():def __init__(self, start, end, interval=None):
self.start = start
self.end = end
self.interval = interval
def __iter__(self):
return self
def next(self):
if self.start < self.end:
if self.interval:
self.start += self.interval
return self.start - self.interval
else:
self.start += 1
return self.start - 1
else:
raise StopIteration
for i in custom_iterator(1, 10):
print i
"Iterator means to interate value one by one from the sequence. In custom iterator we need to create class which shoud be iterated by __iter__ function so that to implement iter functionality. Here, we can pass two argument with default interval, if we want custom interval also then we will pass three arguments in custom iterator like custom_iterator(1, 10, 2)"
Generator
def custom_generator(start, end, interval=None):while start < end:
yield start
if interval:
start += interval
else:
start += 1
else:
raise StopIteration
for j in custom_generator(1, 10, 2):
print j
"Don't forget yield statment whenever we will talk about generator, it used to store currrent status of the function and continue with previous state, this type of function also called co-routing function".
Decorator
def first_decorator(func):def wrapper_function(*args, **kwargs):
# here can code for extra functionality
return func(*args, **kwargs)
return wrapper_function
@first_decorator
def add_val(x, y):
return x + y
print "val", add_val(10, 20)
"Decorator means pass the function as arguments in other function, why we need to do this type of implementation because object oriented concept is write once read many times, to proof this concept without any changes in previos function we will add new funtionality in newly created function".
Exception
class CustomError(Exception):def __init__(self, arg):
# Set some exception infomation
self.msg = arg
try:
# Raise an exception with argument
raise CustomError('This is a CustomError')
except CustomError, arg:
# Catch the custom exception
print 'Error: ', arg.msg
"Custom Eception, where user will create own exception class and based on the condition will raise error message".
Enjoy ... :)
