[Python] List intersection, union, difference

1. Get the intersection of two lists
print list(set(a).intersection(set(b)))

2. Get the union of two lists

print list(set(a).union(set(b)))

3. Get the difference of two lists

print list(set(b).difference(set(a))) # There is in b but not in a

 

2.python Set intersection, union, difference

s = set([3,5,9,10,20,40]) #Create a numeric set 

t = set([3,5,9,1,7,29,81]) #Create a set of values 

a = t | s # The union of t and s, equivalent to t.union(s)

b = t & s # The intersection of t and s, equivalent to t.intersection(s) 

c = t-s # Difference set (item is in t, but not in s), equivalent to t.difference(s) 

d = t ^ s # Symmetric difference set (items are in t or s, but will not appear in both), equivalent to t.symmetric_difference(s)

 

@差集(Dictionary)

（1）

if __name__ == '__main__':
    a_list = [{'a' : 1}, {'b' : 2}, {'c' : 3}, {'d' : 4}, {'e' : 5}]
    b_list = [{'a' : 1}, {'b' : 2}]
    ret_list = []
    for item in a_list:
        if item not in b_list:
            ret_list.append(item)
    for item in b_list:
        if item not in a_list:
            ret_list.append(item)
    print(ret_list)

（2）

if __name__ == '__main__':
    a_list = [{'a' : 1}, {'b' : 2}, {'c' : 3}, {'d' : 4}, {'e' : 5}]
    b_list = [{'a' : 1}, {'b' : 2}]
    ret_list = [item for item in a_list if item not in b_list] + [item for item in b_list if item not in a_list]
    print(ret_list)

参考link：http://www.cnblogs.com/DjangoBlog/p/3510385.html

                http://www.jb51.net/article/93166.htm