简单描述：在Range的方法中，它会生成一个list的对象，但是在XRange中，它生成的却是一个xrange的对象，当返回的东西不是很大的时候，或者在一个循环里，基本上都是从头查到底的情况
简单描述：
在Range的方法中，它会生成一个list的对象，但是在XRange中，它生成的却是一个xrange的对象，当返回的东西不是很大的时候，或者在一个循环里，基本上都是从头查到底的情况下，这两个方法的效率差不多。但是，当返回的东西很大，或者循环中常常会被Break出来的话，还是建议使用XRange，这样既省空间，又会提高效率。
上代码：
>>> help(range)
Help on built-in function range in module __builtin__:range(...) range([start,] stop[, step]) -> list of integers Return a list containing an arithmetic progression of integers. range(i, j) returns [i, i+1, i+2, ..., j-1]; start (!) defaults to 0. When step is given, it specifies the increment (or decrement). For example, range(4) returns [0, 1, 2, 3]. The end point is omitted! These are exactly the valid indices for a list of 4 elements.>>> help(xrange)Help on class xrange in module __builtin__:class xrange(object)| xrange([start,] stop[, step]) -> xrange object| | Like range(), but instead of returning a list, returns an object that| generates the numbers in the range on demand. For looping, this is| slightly faster than range() and more memory efficient.| | Methods defined here:| | __getattribute__(...)| x.__getattribute__('name') x.name| | __getitem__(...)| x.__getitem__(y) x[y]| | __iter__(...)| x.__iter__() iter(x)| | __len__(...)| x.__len__() len(x)| | __reduce__(...)| | __repr__(...)| x.__repr__() repr(x)| | __reversed__(...)| Returns a reverse iterator.| | ----------------------------------------------------------------------| Data and other attributes defined here:| | __new__ = | T.__new__(S, ...) -> a new object with type S, a subtype of T>>> a = range(100)>>> print type(a)>>> print a[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]>>> a = xrange(100)>>> print type(a)>>> print axrange(100)