Python参数传递机制：到底是传值还是传引用？

参考链接：http://c.biancheng.net/view/2258.html

def A(matrix, string):
    for i in range(len(matrix)):
        for j in range(len(matrix[i])):
            print(matrix[i][j])
    print(string)

def B(matrix, string):
    matrix[0][0] = 0
    for i in range(len(matrix)):
        for j in range(len(matrix[i])):
            print(matrix[i][j]) 
    string[0] = '1'
    print(string)
                

matrix = [[1, 2], [3, 4]]
string = ['haha', 'nihao']
A(matrix, string) 

B(matrix, string)

输出结果

1
2
3
4
['haha', 'nihao']
0
2
3
4
['1', 'nihao']