Python列表：元素的修改、添加、删除和排序

本文参考自《Python编程：从入门到实践》，作者：Eric Matthes，译者：袁国忠

操作	语法	举例	结果
修改元素		motocycles = ['honda', 'yamaha', 'suzuki'] print (motocycles) motocycles[0] = 'ducati' print (motocycles)	['honda', 'yamaha', 'suzuki'] ['ducati', 'yamaha', 'suzuki']
添加元素	在列表末尾添加元素：append()	motocycles = ['honda', 'yamaha', 'suzuki'] print (motocycles) motocycles.append('ducati') print (motocycles)	['honda', 'yamaha', 'suzuki']   ['honda', 'yamaha', 'suzuki', 'ducati']
	在列表中插入元素：insert()	motocycles = ['honda', 'yamaha', 'suzuki'] print (motocycles) motocycels.insert(0, 'ducati') print (motocycles)	['honda', 'yamaha', 'suzuki'] ['ducati', 'honda', 'yamaha', 'suzuki']
删除元素	根据索引删除：del，无法继续使用	motocycles = ['honda', 'yamaha', 'suzuki'] print (motocycles) del motocycles[1] print (motocycles)	['honda', 'yamaha', 'suzuki'] ['honda', 'suzuki']
	删除末尾的元素：pop()，可以继续使用 也可以根据索引删除，如motocycles.pop(0)	motocycles = ['honda', 'yamaha', 'suzuki'] print (motocycles) popped_motocycle = motocycles.pop() print (motocycles) print (popped_motocycle)	['honda', 'yamaha', 'suzuki'] ['honda', 'yamaha'] suzuki
	不知道索引时，根据值删除元素：remove()，可以继续使用	motocycles = ['honda', 'yamaha', 'suzuki'， 'ducati'] print (motocycles) too_expensive = 'ducati' motocycles.remove(too_expensive) print (motocycles) print (too_expensive)	['honda', 'yamaha', 'suzuki', 'ducati'] ['honda', 'yamaha', 'suzuki'] ducati
元素排序	无返回值，彻底改变原值 永久性排序：sort() 反方向排序：sort(reverse = True)	cars = ['bmw', 'audi', 'toyota', 'subaru'] print (cars) cars.sort() print (cars) cars = ['bmw', 'audi', 'toyota', 'subaru'] cars.sort(reverse = True) print (cars)	['bmw', 'audi', 'toyota', 'subaru'] ['audi', 'bmw', 'subaru', 'toyota'] ['toyota', 'subaru', 'bmw', 'audi']
	有返回值，原值不会变 临时性排序：sorted() 反方向排序：sorted(reverse = True)	cars = ['bmw', 'audi', 'toyota', 'subaru'] print (cars) print (sorted(cars)) print (cars)	['bmw', 'audi', 'toyota', 'subaru'] ['audi', 'bmw', 'subaru', 'toyota'] ['bmw', 'audi', 'toyota', 'subaru']
	无返回值，彻底改变原值 永久性反转列表元素的排列顺序：reverse()	cars = ['bmw', 'audi', 'toyota', 'subaru'] print (cars) cars.reverse() print (cars) cars.reverse() print (cars)	['bmw', 'audi', 'toyota', 'subaru'] ['subaru', 'toyota', 'audi', 'bmw'] ['bmw', 'audi', 'toyota', 'subaru']
	有返回值，不会改变原值 临时性反转列表的排列顺序：[: : -1]	num = [1, 2, 3, 4] num_new = num[::-1] print(num_new) print(num)	[4, 3, 2, 1] [1, 2, 3, 4]
合并列表	+或extend	A = [1, 2, 3, 4] B = [5, 6, 7, 8] A = A + B 或 A.extend(B) print(A)	[1, 2, 3, 4, 5, 6, 7, 8]