python list

切片：

>>> bag = range(20)
>>> bag
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]

>>> for i in range(0, len(bag),3):
... print bag[i:i+3]
... 
[0, 1, 2]
[3, 4, 5]
[6, 7, 8]
[9, 10, 11]
[12, 13, 14]
[15, 16, 17]
[18, 19]

>>> bag[::-1] #翻转List
[19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

>>> bag[:10] #取前10个
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

>>> bag[-10:] #取后10个
[10, 11, 12, 13, 14, 15, 16, 17, 18, 19]

排序：

>>> sorted([10,30,50,20,40])
[10, 20, 30, 40, 50]
>>> sorted([10,30,50,20,40],reverse=True)
[50, 40, 30, 20, 10]

>>> students = [('e', 'A', 15), ('f', 'D', 12), ('g', 'B', 10)]   
>>> print(sorted(students,cmp=lambda x,y : cmp(x[0], y[0]),reverse=False))
[('e', 'A', 15), ('f', 'D', 12), ('g', 'B', 10)]
>>> print(sorted(students,cmp=lambda x,y : cmp(x[1], y[1]),reverse=False))
[('e', 'A', 15), ('g', 'B', 10), ('f', 'D', 12)]
>>> print(sorted(students,cmp=lambda x,y : cmp(x[2], y[2]),reverse=False))
[('g', 'B', 10), ('f', 'D', 12), ('e', 'A', 15)]