I. access multi elements of a list knowing their indices

You can use operator.itemgetter:

>>>from operator import itemgetter

>>> a =[-2,1,5,3,8,5,6]

>>> b =[1,2,5]

>>>print itemgetter(*b)(a)(1,5,5)

Or you can use numpy:

>>>import numpy as np

>>> a = np.array([-2,1,5,3,8,5,6])

>>> b =[1,2,5]>>>print list(a[b])[1,5,5]

Or you can

>>>a =[-2,1,5,3,8,5,6]

>>>b =[1,2,5]

>>>c =[ a[i]for i in b]

II.Get the difference set of two lists

>>>list(set(temp1)- set(temp2))