Python学习笔记之集合的概念和简单使用示例

numbers = [1, 2, 6, 3, 1, 1, 6]
unique_nums = set(numbers)
print(unique_nums) # {1, 2, 3, 6}

fruit = {"apple", "banana", "orange", "grapefruit"} # define a set
print("watermelon" in fruit) # False
fruit.add("watermelon") # add an element
print(fruit) # {'grapefruit', 'orange', 'watermelon', 'banana', 'apple'}
print(fruit.pop()) # remove a random element: grapefruit
print(fruit) # {'orange', 'watermelon', 'banana', 'apple'}

a = [1, 2, 2, 3, 3, 3, 4, 4, 4, 4]
b = set(a)
print(len(a) - len(b)) # 6

a = [1, 2, 2, 3, 3, 3, 4, 4, 4, 4]
b = set(a)
b.add(5)
b.pop()