xrange and range in python


python range会生成一个list对象,然后返回list中的内容,而xrange不会生成list对象。所以xrange相对与range来说更省空间,并且速度较快。


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.

ok. Do you understand?