Extracting a range of data from a python list
This question already has an answer here:
 You should do list[44:49] rather than list[44:5] .  Usually when you want to fetch 5 items after (including) the a+1th item, you do L[a, a+5] .  'Usually' implies there are more flexible ways to do so: see Extended Slices: http://docs.python.org/release/2.3/whatsnew/section-slices.html.  
 Also try not to use list as your list name.  It overwrites list() .  
It is list[starting:ending] not list[starting:length].
 So you should do list[44:49]  
For more information on slice notation click here
 In the slice notation [a:b] , the second value ( b ) is not length, but a upper bound.  
 To get five elements starting from 44 you should use [44:49] (49 = 44 + 5)  
If upper bound is smaller than lower bound, you get empty sequence.
链接地址: http://www.djcxy.com/p/26744.html上一篇: 切片操作员理解
下一篇: 从python列表中提取一系列数据
