Python入门·列表
- 列表排序
numbers_1=list(range(0,21,2))
>>> print(numbers_1)
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20]
>>> numbers_2=[]
>>> for value in range(1,20,2):
numbers_2.append(value)
print(numbers_2)
[1]
[1, 3]
[1, 3, 5]
[1, 3, 5, 7]
[1, 3, 5, 7, 9]
[1, 3, 5, 7, 9, 11]
[1, 3, 5, 7, 9, 11, 13]
[1, 3, 5, 7, 9, 11, 13, 15]
[1, 3, 5, 7, 9, 11, 13, 15, 17]
[1, 3, 5, 7, 9, 11, 13, 15, 17, 19]
>>> print(numbers_2)
[1, 3, 5, 7, 9, 11, 13, 15, 17, 19]
>>> print(numbers_1[0:3])
[0, 2, 4]
>>> print(numbers_1[:3])
[0, 2, 4]
>>> print(numbers_1[3:])
[6, 8, 10, 12, 14, 16, 18, 20]
>>> print(numbers_1[-8:])
[6, 8, 10, 12, 14, 16, 18, 20]
>>> numbers_3=[]
>>> numbers_3.append(numbers_1)
>>> numbers_3.append(numbers_2)
>>> print(numbers_3)
[[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20], [1, 3, 5, 7, 9, 11, 13, 15, 17, 19]]
>>> numbers_4=[]
>>> numbers_4.extend(numbers_1)
>>> numbers_4.extend(numbers_2)
>>> print(numbers_4)
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19]
>>> numbers_4.sort()
>>> print(numbers_4)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
对新组成的列表numbers_4进行升序排列，使用了sort()函数，当进行降序排列时，sort()括号中使用reverse=True即可。
numbers_4.sort(reverse=True)
>>> print(numbers_4)
[20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]- 切片
在表示切片的方括号内指定第三个值，可以确定元素提取间隔，例如[0:10:2]，0为切片起始索引，10（9）为切片结束索引，切片间隔为2，对numbers_4列表进行切片，输出应为20-11这十个数中的偶数。
>>> print(numbers_4[0:10:2])
[20, 18, 16, 14, 12]