python数据类型-集合（简单实用）

集合的定义

python提供的内置数据结构，属于可变序列
理解为没有value的字典，使用hash存储

创建集合

# 花括号创建
set1 = {2, 5, 3, 6, 8}
print(set1)

# 内置函数set
set1 = set(range(6))
print(set1)
set1 = set([1, 2, 3])
print(set1)

# 创建空集合要用set，用花括号会被识别成字典

集合相关操作

# 添加元素
set1 = {2, 5, 3, 6, 8}
set1.add(9)
print(set1)

# 添加多个元素
set1 = {2, 5, 3, 6, 8}
a = [4, 10]
set1.add(a)
print(set1)

# 删除元素
# remove (元素不存在会报错)
set1 = {2, 5, 3, 6, 8}
set1.remove(1)
print(set1)
# discard (元素不存在不会报错)
set1.discard(3)
print(set1)
# pop：随即删除
set1.pop()
print(set1)
# clear：删除全部值
set1.clear()
print(set1)

# 判断元素是否存在
set1 = {2, 5, 3, 6, 8}
print(2 in set1)
print(3 not in set1)

# 数学判断和操作
set1 = {2, 5, 3, 6, 8}
set2 = {5, 3}
set3 = {6, 8, 0}
print(set2.issubset(set1)) # set2是set1子集输出True
print(set1.issuperset(set2)) # set1是set2超集输出True
print(set1.isdisjoint(set2)) # 没有交集输出True
print(set1.intersection(set2)) # 取交集
print(set1 & set3) # 取交集
print(set1.union(set2)) # 取并集
print(set1 | set3) # 取并集
print(set1.difference(set2)) # 取差集
print(set1 - set3) # 取差集

# 集合生成式
set1 = {i for i in range(10)}