Python 中set集合类型（去重、成员运算）

# 第一种、创建集合，使用花括号{}，打印默认去重
one_set = {10, 20, 33, 10, 22, 33, 20}
print(one_set)

# 第二种、创建集合，使用花括号set({值})，打印默认去重
two_set = set([10, 10, 20, 44, 10, 66, 44, 20])
print(two_set)

# 创建空集合
# 不能使用{}来创建空集合，默认创建的是空字典
empty_set = set()
print(type(empty_set))

执行结果：
{33, 10, 20, 22}
{10, 20, 66, 44}
<class 'set'>

one_set1 = set([10, 20, 33, 10, 22, 33, 20])
two_set1 = set({10, 10, 20, 44, 10, 66, 44, 20})

# 求交集，去重之后公共元素, & 及 .intersection（译：因特塞克神）
result_set1 = one_set1 & two_set1
result_set11 = one_set1.intersection(two_set1)
print(result_set1)      # 结果：{10, 20}
print(result_set11)     # 结果：{10, 20}

# 求并集，合并在一起，
result_set2 = one_set1 | two_set1
result_set22 = one_set1.union(two_set1)                   # （译：有你恩呢）
print(result_set2)      # 结果：{33, 66, 10, 44, 20, 22}
print(result_set22)     # 结果：{33, 66, 10, 44, 20, 22}


# 求差集，只在其中一个，不在另一个
result_set3 = one_set1 - two_set1
result_set33 = one_set1.difference(two_set1)             # （译：地府云词）
print(result_set3)          # 结果：{33, 22}
print(result_set33)        # 结果：{33, 22}


# 对称差集，要么在A，要么在B，没有公共元素
result_set4 = one_set1 ^ two_set1
result_set44 = one_set1.symmetric_difference(two_set1)
print(result_set4)          # 结果：{33, 66, 44, 22}
print(result_set44)         # 结果：{33, 66, 44, 22}

# 如何判断一个元素是否在其中
# 判断33是否在one_set1
a = 33 in one_set1