通过代码来直观理解:
fuse_layers
= [ ['a','b','AB'] , ['c','d','CD'] , ['e','f','CF'] ,['g','h','GH'] , ['i','j','IJ']]
fuse_layers
[2][1]
fuse_layers
[3][2]
理解起来很简单,比如fuse_layers[2][1]: [2]代表大列表中下标为2的元素,即[‘e’,‘f’,‘CF’],这个元素也是个列表 [1]代表上面[‘e’,‘f’,‘CF’]这个元素中下标为1的元素,即 ‘f’