集合的创建:使用内置函数set()进行转化或者使用{}包括起来的,集合中的元素:无序性,互异性,确定性。
举例:
numbers=set(range(0,7))//使用内置函数进行转化 print(numbers) print(type(numbers))
{0, 1, 2, 3, 4, 5, 6} <class 'set'>
互异性:
fruit={'apple','orange','banana',"apple",'apple','orange','banana',"apple"} print(fruit) print(type(fruit))
{'apple', 'banana', 'orange'} <class 'set'>
无序性:集合中的元素不能通过下标访问。
举例:
fruit =set({'apple',9,"axn","dbu",12}) print(fruit[2])
集合中的操作函数:
在集合中添加元素:add() 函数
举例:
fruit =set({'apple',9,"axn","dbu",12}) fruit.add("bc") print(fruit)
{'bc', 'apple', 9, 12, 'dbu', 'axn'}
删除集合中的第一个元素:pop()函数
举例:
fruit =set({'apple',9,"axn","dbu",12}) fruit.pop() print(fruit)
{'apple', 9, 12, 'axn'}
删除集合中的指定元素:
1:remove()函数,若该元素不存在则会报错
举例:
fruit =set({'apple',9,"axn","dbu",12}) fruit.remove("banana") print(fruit)
fruit =set({'apple',9,"axn","dbu",12,"apple"}) fruit.remove("apple") print(fruit)
{'dbu', 'axn', 9, 12}
2:discard()函数,若指定元素不存在不会报错。
举例:
fruit =set({'apple',9,"axn","dbu",12,"apple"}) fruit.discard("banana") print(fruit)
{'dbu', 'apple', 9, 'axn', 12}
fruit =set({'apple',9,"axn","dbu",12,"apple"}) fruit.discard("apple") print(fruit)
{'dbu', 'axn', 9, 12}
判断元素是否在集合里面:if in/not in语句
举例:
fruit =set({'apple',9,"axn","dbu",12,"apple"}) if "apple" in fruit: print("yes") else: print("NO") if "banana" not in fruit: print("YES") else: print("NO")
yes YES
集合的遍历:for循环
fruit =set({'apple',9,"axn","dbu",12,"apple"}) for i in fruit: print(i,end=' ')
axn 9 apple 12 dbu
集合元素个数的计算:len()函数
举例:
fruit =set({'apple',9,"axn","dbu",12,"apple"}) print(len(fruit))
5//注意集合元素的唯一性特征
集合与字典,列表,元组的嵌套:
集合与字典:
s1=set({"name":"jason","age":19,"地址":"北京市"}) print(s1) print(type(s1))
{'地址', 'name', 'age'}//只输出键名 <class 'set'>
集合与元组:
举例:
s1={("name","jason","age",19,"地址","北京市"),12,34,0} print(s1) print(type(s1))
{0, 34, ('name', 'jason', 'age', 19, '地址', '北京市'), 12} <class 'set'>
使用内置函数进行转化:
s1=set({"name","jason","age",19,"地址","北京市"}) print(s1) print(type(s1))
{'age', 'jason', 19, '地址', '北京市', 'name'} <class 'set'>
集合与列表:
举例:
s2=set(["name","jason","age",19,"地址","北京市"]) print(s2) print(type(s2))
{'北京市', 'age', 'jason', 19, 'name', '地址'} <class 'set'>