lis = [1, 2, 3, 4]
lis - [1]
lis.pop(i)
data = (  
    "this is a string", [1, 2, 3, 4], ("more tuples",  
    1.0, 2.3, 4.5), "this is yet another string"  
    )
print data
import pprint
pprint.pprint(data)
i = "a"
j = "b"
k = "c"
set(i + j + k)
%hist -f "美观打印和集合的操作.py"
