python list

nums = [5,4,2,7,9,8,1,3,3]
//排序从小到大
nums.sort()

//排序从大到小
nums.reverse()# 结合 nums.sort(reverse=True)

//查找元素个数
nums.count(3)
print(nums.count(3))

//查找元素下标
nums = [5,4,2,7,2,9,8,1,3,3]
nums.index(2,0,9)
print(nums.index(2,0,9))

//浅拷贝
nums = [5,4,2,7,2,9,8,1,3,3]
nums_copy2 = nums.copy()
print(nums_copy2)

//深拷贝
import copy
x = [[1,2,3],[4,5,6,],[7,8,9]]
y = copy.deepcopy(x)
x [1][1] = 0
print(x)
print(y)

//矩阵
matrix = [[1,2,3],
[4,5,6],
[7,8,9]]
for i in matrix:
for each in i:
print(each,end=' ')
print()
/print(matrix[2][2])

创建三个一样的列表
a = [0] * 3
for i in range(3):
a[i] = [0] * 4
print(a)
不同于b = [[0] * 3 ] * 3
区别：名字一样的三个人和叫三声一个人的名字
is：查看是否相同“print(a[0] is a[1])”

列表推导式
cb = [1,2,3,4,5,6]
cb = [i * 2 for i in cb]
print(cb)
输出结果：【2，4，6，8，10，12】