集合

集合

由不同的元素组成的集合，不可定义相同的元素，如果定义了相同的元素，那么只有一个元素生效。集合是一组无序列的可hash值，可以作为字典的key.

 

s={1,2,3,4,5,"ali"}
print(type(s))

　　

s = set("hello")
print(s)

　　

s = set(["ali","sb","ali"])
print(s)

　　

add方法，增加

s = set(["ali","sb","ali"])
s.add("s")
print(s)

　　

clear方法，清空

s = set(["ali","sb","ali"])
s.clear()
print(s)

　　

copy方法，复制

s = set(["ali","sb","ali"])
s1 = s.copy()
print(s1)

　　

pop方法，随机删除并且取出元素

s = set(["ali","sb","ali"])
s1 = s.pop()
print(s1)

　　

remove方法，删除指定元素

s = {"ali","sb","heihei"}
s.remove("sb")
print(s)

　　

discard方法删除注定元素，如果元素不存在不会报错

s = {"ali","sb","heihei"}
s.discard("sb")
print(s)

　　

将列表转换为集合

python_l = ["ali","heihei","hehe"]
linux_l = ["ali","heihei"]
p_s = set(python_l)
print(p_s)

　　

intersection和&方法，取两个集合的交集

python_l = ["ali","heihei","hehe"]
linux_l = ["ali","heihei"]
p_s = set(python_l)
l_s = set(linux_l)
print(p_s.intersection(l_s))

print(p_s&l_s)

　　

union方法和|方法，取两个集合的并集

python_l = ["ali","heihei","hehe"]
linux_l = ["ali","heihei","lala"]
p_s = set(python_l)
l_s = set(linux_l)
print(p_s.union(l_s))
print(p_s|l_s)

　　

difference方法和-方法，取两个集合的差集

python_l = ["ali","heihei","hehe"]
linux_l = ["ali","heihei","lala"]
p_s = set(python_l)
l_s = set(linux_l)
print(p_s.difference(l_s))
print(p_s-l_s)
print(l_s-p_s)

　　

symmetric_difference方法，取两个集合的交叉补集

python_l = ["ali","heihei","hehe"]
linux_l = ["ali","heihei","sb"]
p_s = set(python_l)
l_s = set(linux_l)
print(p_s.symmetric_difference(l_s))
print(p_s^l_s)
print(l_s^p_s)