如下两段代码:
代码1:
aa = [[1, 2], [2, 3], [3, 4]]
qq = aa[0]
qq[1] = 0
print(aa)#[[1, 0], [2, 3], [3, 4]]#aa被改变了
代码2:
aa = [[1, 2], [2, 3], [3, 4]]
qq = aa[0]
qq = [8, 8]
print(aa)#[[1, 2], [2, 3], [3, 4]]#aa没有被改变
为何代码1中aa被改变了?qq获得的是值拷贝还是引用?