Difference between <type 'generator'> and <type 'xrange'>

Question

I have seen in a lot of posts/materials saying xrange(num) is a generator/iterator. I have a couple of questions regarding that.

1. I want to know the exact difference between type 'xrange' and type 'generator'

2. If xrange is an iterator/generator, it is supposed to have .next() method. I do not understand why the .next() method doesn't work for the case below.

   def generator():
       for i in xrange(20): yield i
   

   In the above example,

       numbers = generator()
       for i in numbers: 
           if i == 6: break
   
       for i in numbers:
           if i == 10: break
           print i
   
       >>> 7
       8
       9
   
       >>> print numbers.next()
       11 
   

   The above functionalities also hold true for a object generator of the type:

       >>> numbers = (x for x in range(100))
   

   If I do with xrange operation, the loop starts iterating from the beginning and there is no next() operation. I know that we can do the smart way of:

       for i in xrange(20):
           if (#something):
               var = i
               break
        #perform some operations
        for i in range(var,20):
            #Do something
   

But I want to loop to continue after var without using var.

To be short, is there a next() kind of operation for xrange. If yes : 'How?' , else : 'Why?'

Answer 1

xrange is an iterable, so you can call iter to get an iterator out of it.

>>> x = xrange(20)
>>> iterator = iter(x)
>>> for i in iterator:
...     if i == 6: break
...
>>> iterator.next()
7