元组
- 创建一系列不可修改的元素,Python中不能修改的值称为不可变的,不可变的列表称为元祖。
定义元组
- 使用圆括号而不是方括号来标识,定义元组后可以用索引来访问其元素
dimensions = (200,50)
print(dimensions[0])
print(dimensions[1])
dimensions[0] = 250
200
50
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-2-2db727e7a6e4> in <module>()
4 print(dimensions[0])
5 print(dimensions[1])
----> 6 dimensions[0] = 250
TypeError: 'tuple' object does not support item assignment
遍历元组中的所有值
dimensions = (200,50)
for dimension in dimensions:
print(dimension)
200
50
修改元组变量
- 虽然不能修改元组的值,但可以给存储元组的变量赋值(重新定义整个元组)
dimensions = (200,50)
print("Original dimensions:")
for dimension in dimensions:
print(dimension)
dimensions = (400,100)
print("\nModified dimensions:")
for dimension in dimensions:
print(dimension)
Original dimensions:
200
50
Modified dimensions:
400
100
练习
restaurant = ("西红柿","黄瓜","水蜜桃","腊肉","红烧肉")
for food in restaurant:
print(food)
restaurant[1] = "茄子"
西红柿
黄瓜
水蜜桃
腊肉
红烧肉
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-8-9cdf694f1019> in <module>()
7 for food in restaurant:
8 print(food)
----> 9 restaurant[1] = "茄子"
10 restaurant = ("西红柿","黄瓜","水蜜桃","香蕉","番茄")
11 for foods in restaurant:
TypeError: 'tuple' object does not support item assignment
restaurant = ("西红柿","黄瓜","水蜜桃","香蕉","番茄")
for foods in restaurant:
print(foods)
西红柿
黄瓜
水蜜桃
香蕉
番茄