Python基础： 列表

列表是按特定顺序排列的项的集合，可以包含任何类型的数据。

语法：列表使用方括号 创建，元素用逗号分隔。

bicycles = ['trek', 'cannondale', 'redline', 'specialized'] print(bicycles)#Output ['trek', 'cannondale', 'redline', 'specialized']

访问元素：使用索引访问元素，从 0 开始。负索引可用于访问列表末尾的元素。

bicycles = ['trek', 'cannondale', 'redline', 'specialized'] print(bicycles[0])#Output trekbicycles = ['trek', 'cannondale', 'redline', 'specialized'] print(bicycles[0].title)#OutPutTrek

可以使用 append、insert、del、pop 和 remove 等各种方法更改、添加或删除元素。

向列表添加元素

motorcycles = ['honda', 'yamaha', 'suzuki'] print(motorcycles)#Outuput ['honda', 'yamaha', 'suzuki'] motorcycles.append('Ducati') print(motorcycles)#Output ['honda', 'yamaha', 'suzuki', 'ducati']

将元素插入 List

motorcycles = ['honda', 'yamaha', 'suzuki'] motorcycles.insert(0, 'ducati') print(motorcycles)#Output ['ducati', 'honda', 'yamaha', 'suzuki']

从 List 中删除元素

motorcycles = ['honda', 'yamaha', 'suzuki'] print(motorcycles) del motorcycles[0] print(motorcycles)#Output ['honda', 'yamaha', 'suzuki'] ['yamaha', 'suzuki']

使用 pop 方法删除项

motorcycles = ['honda', 'yamaha', 'suzuki'] print(motorcycles) popped_motorcycle = motorcycles.pop print(motorcycles) print(popped_motorcycle)#Output ['honda', 'yamaha', 'suzuki'] ['honda', 'yamaha'] suzuki motorcycles = ['honda', 'yamaha', 'suzuki'] last_owned = motorcycles.pop print(f"The last motorcycle I owned was a {last_owned.title}.")#Output The last motorcycle I owned was a Suzuki.

从列表中的任意位置弹出项目

motorcycles = ['honda', 'yamaha', 'suzuki'] first_owned = motorcycles.pop(0) print(f"The first motorcycle I owned was a {first_owned.title}.")#Output The first motorcycle I owned was a Honda.

按值删除项

motorcycles = ['honda', 'yamaha', 'suzuki', 'ducati'] print(motorcycles) motorcycles.remove('ducati') print(motorcycles)#Output ['honda', 'yamaha', 'suzuki', 'ducati'] ['honda', 'yamaha', 'suzuki']motorcycles = ['honda', 'yamaha', 'suzuki', 'ducati'] print(motorcycles)too_expensive = 'ducati'motorcycles.remove(too_expensive) print(motorcycles)print(f"\nA {too_expensive.title} is too expensive for me.")#Output ['honda', 'yamaha', 'suzuki', 'ducati'] ['honda', 'yamaha', 'suzuki'] A Ducati is too expensive for me.

使用 sort 方法对列表进行永久排序：

使用 sort 按字母顺序对列表进行排序。cars = ['bmw', 'audi', 'toyota', 'subaru'] cars.sort print(cars)>> ['audi', 'bmw', 'subaru', 'toyota']还可以使用 sort（reverse=True） 反向排序。cars = ['bmw', 'audi', 'toyota', 'subaru'] cars.sort(reverse=True) print(cars)>> ['toyota', 'subaru', 'bmw', 'audi']

临时对列表进行排序：

使用 sorted 对列表进行临时排序，而不改变原始顺序。 cars = ['bmw', 'audi', 'toyota', 'subaru']print("Here is the original list:") print(cars)print("\nHere is the sorted list:") print(sorted(cars))print("\nHere is the original list again:") print(cars)>>Here is the original list: ['bmw', 'audi', 'toyota', 'subaru']Here is the sorted list: ['audi', 'bmw', 'subaru', 'toyota']Here is the original list again: ['bmw', 'audi', 'toyota', 'subaru']

反转列表：

使用 reverse 反转列表的顺序。 cars = ['bmw', 'audi', 'toyota', 'subaru'] print(cars) cars.reverse print(cars)>> ['bmw', 'audi', 'toyota', 'subaru'] ['subaru', 'toyota', 'audi', 'bmw']

求列表的长度：

使用 len 查找列表中的项数。>>> cars = ['bmw', 'audi', 'toyota', 'subaru'] >>> len(cars)>> 4

排序注意事项：在处理大小写混合值时，排序会变得复杂，并且可能需要其他注意事项才能正确排序。

常见索引错误：

当尝试访问列表中不存在的索引时，会发生这种情况。motorcycles = ['honda', 'yamaha', 'suzuki'] print(motorcycles[3])# This example results in an index error:Traceback (most recent call last): File "motorcycles.py", line 2, in print(motorcycles[3]) ~~~~~~~~~~~^^^ IndexError: list index out of range

Python 列表是零索引的;第一项位于索引 0 处。
第三项是通过摩托车[2]访问的，而不是用摩托车[3] 来访问的。

访问最后一项：

使用 -1 可访问列表的最后一项。motorcycles = ['honda', 'yamaha', 'suzuki'] print(motorcycles[-1])#The index -1 always returns the last item in a list, in this case the value 'suzuki'>>suzuki访问空列表中的最后一项（例如 motorcycles[-1]）也会导致 IndexError。motorcycles = print(motorcycles[-1])# No items are in motorcycles, so Python returns another index error:Traceback (most recent call last): File "motorcyles.py", line 3, in print(motorcycles[-1]) ~~~~~~~~~~~^^^^ IndexError: list index out of range

故障排除：如果您遇到 IndexError，请使用 len 检查列表的长度或打印列表以了解其内容。