1.
a
=
[
]
arrays
=
[
a
*
3
]
arrays其实为
[[]]
2.
arrays
=
[
a
]
*
N
看上去是创建了二维数组，但是只是创建N个指向a的引用，所以一旦a改变，arrays中N个list也会随之改变
eg:
a
=
[
]
N
=
3
arrays
=
[
a
]
*
3
arrays
[
0
]
.
append
(
1
)
#看上去只为第一个list添加整数
1
，实际上
--
-
print
(
arrays
)
输出为
[[1], [1], [1]]
3.
arrays
=
[
[
]
for
i
in
range
(
N
)
]
eg:
N
=
3
arrays
=
[
[
]
for
i
in
range
(
N
)
]
print
(
arrays
)
输出为
[[], [], []]
