python基础-集合set { }

集合的定义和操作

集合的特性：

# 定义集合
my_set = {"world", "hello", "world", "hello", "str"}
my_set_empty = set()  # 定义空集合
print(f"my_set的内容是：{my_set},类型是：{type(my_set)}")
print(f"my_set_empty的内容是：{my_set_empty},类型是：{type(my_set_empty)}")

# 添加新元素
my_set.add("python")
my_set.add("hello")
print(f"添加新元素后：{my_set}")

# 移除元素
my_set.remove("hello")
print(f"移除元素后：{my_set}")

# 随机取出一个元素
my_set = {"world", "hello", "world", "hello", "str"}
element = my_set.pop()
print(f"随机取出一个元素：{element},取出元素后：{my_set}")

# 清空元素，clear
my_set.clear()
print(f"清空后：{my_set}")

# 去两个集合的差集
set1 = {1, 2, 3}
set2 = {1, 5, 6}
set3 = set1.difference(set2)
print(f"去差集后的结果是：{set3}")
print(f"去差集后的set1的内容：{set1}")
print(f"去差集后的set2的内容：{set2}")

# 消除两个集合的差集
set1 = {1, 2, 3}
set2 = {1, 5, 6}
set1.difference_update(set2)
print(f"消除差集后，集合1的内容：{set1}")
print(f"消除差集后，集合2的内容：{set2}")

# 两个集合合并为1个
set1 = {1, 2, 3}
set2 = {1, 5, 6}
set3 = set1.union(set2)
print(f"两个集合合并结果：{set3}")
print(f"合并后集合1：{set1}")
print(f"合并后集合2：{set2}")

# 统计集合元素数量len()
set1 = {1,2,3,4,5,1,2,3,4,5}
num = len(set1)
print(num)

# 只能用for遍历 集合不能用下标定位
set1 = {1,2,3,4,5}
for i in set1:
    print(i)
 
# 信息去重
my_list =['黑马程序员','传智播客','黑马程序员',
          '传智播客','itheima','itcast','itheima','itcast','best']
set1 = set()
print(type(set1))
for i in my_list:
    set1.add(i)
print(set1)