xrange属于类,继承自object.
用法:
xrange(stop) -> xrange object
xrange(start, stop[, step]) -> xrange object

range属于函数,返回list,而xrange返回xrange object.对于循环而言,稍快于range(),内存效率更高.

#!/usr/bin/python
# -*- coding: UTF- -*-
n =
for c in xrange(n):
    print c

 format()　　格式化输出字符串，format(value, format_spec)实质上是调用了value的__format__(format_spec)方法

"I am {0}, I like {1}!".format("wang", "moon")
'I am wang, I like moon!'