028 元组的内置方法
元组类型的内置方法(tuple)
元组是不可变的列表,也就是说元组的值不可以修改,因此元组一般只用于只存不取的需求
1.用途
语族和列表一样可以用来存储多个爱好,多种描述状态等
2.定义
在()内可以又多个任意来行的值,用逗号分隔开元素
hobby_list = ('ran','play','read')
3.常用操作和内置方法
1.索引取值
2.切片
3.长度
4.成员运算in/not in
5.循环
6.count
7.index
1.索引取值
food_tuple = ('apple','banana','orange','grape')
print(food_tuple[0])
# apple
2.切片(顾头不顾尾,步长)
food_tuple = ('apple','banana','orange','grape')
print(food_tuple[:-1])
# ('apple', 'banana', 'orange')
print(food_tuple[::-1])
# ('grape', 'orange', 'banana', 'apple')
3.长度
food_tuple = ('apple','banana','orange','grape')
print(len(food_tuple))
# 4
4.成员运算
food_tuple = ('apple','banana','orange','grape')
print('app' in food_tuple)
# False
print('apple' in food_tuple)
# True
5.循环
food_tuple = ('apple','banana','orange','grape')
for food in food_tuple:
print(food)
# 结果
apple
banana
orange
grape
6.count()
food_tuple = ('apple','banana','orange','grape','apple')
print(food_tuple.count('apple'))
# 2
7.index()
food_tuple = ('apple','banana','orange','grape','apple')
print(food_tuple.index('banana'))
# 0
print(food_tuple.index('apple'))
# 1
4.元组是存放多个值的
5.元组是有序的
name_tuple = ('xichen')
print(id(name_tuple))
# 2474398778232
name_tuple = ('eee')
print(id(name_tuple))
# 2474398778288
6.元组是不可变数据类型
7.元组和列表的区别
1.列表可变的原因是:索引所对应的值的内存地址是可以改变的
2.元组不可变得原因是:索引所对应的值的内存地址是不可以改变的