Question

我有b这是一个列表，它还包含10个列表，列表的每个索引都包含列表本身。现在，当我尝试在第i个列表中添加一些值时，它会将其附加到所有列表中。我不明白为什么？救命。

CODE：

a=[3,5,1,7,2,22,9,8,4,11]
b=[[]]*10
d=10
for i in range(len(a)):         
    b[i].append(a[i])
    print b

输出：

[[3]，[3]，[3]，[3]，[3]，[3]，[3]，[3]，[3]，[3]] [[3,5]，[3,5]，[3,5]，[3,5]，[3,5]，[3,5]，[3,5]，[3,5]，[ 3,5]，[3,5]] [[3,5,1]，[3,5,1]，[3,5,1]，[3,5,1]，[3,5,1]，[3,5,1]，[ 3,5,1]，[3,5,1]，[3,5,1]，[3,5,1]] [[3,5,1,7]，[3,5,1,7]，[3,5,1,7]，[3,5,1,7]，[3,5,1,7] ，[3,5,1,7]，[3,5,1,7]，[3,5,1,7]，[3,5,1,7]，[3,5,1,7] ] [[3,5,1,7,2]，[3,5,1,7,2]，[3,5,1,7,2]，[3,5,1,7,2]，[ 3,5,1,7,2]，[3,5,1,7,2]，[3,5,1,7,2]，[3,5,1,7,2]，[3， 5,1,7,2]，[3,5,1,7,2]] [[3,5,1,7,2,22]，[3,5,1,7,2,22]，[3,5,1,7,2,22]，[3,5,1， 7,2,22]，[3,5,1,7,2,22]，[3,5,1,7,2,22]，[3,5,1,7,2,22]，[ 3,5,1,7,2,22]，[3,5,1,7,2,22]，[3,5,1,7,2,22]] [[3,5,1,7,2,22,9]，[3,5,1,7,2,22,9]，[3,5,1,7,2,22,9]，[ 3,5,1,7,2,22,9]，[3,5,1,7,2,22,9]，[3,5,1,7,2,22,9]，[3， 5,1,7,2,22,9]，[3,5,1,7,2,22,9]，[3,5,1,7,2,22,9]，[3,5] 1,7,2,22,9]] [[3,5,1,7,2,22,9,8]，[3,5,1,7,2,22,9,8]，[3,5,1,7,2,22] 9,8]，[3,5,1,7,2,22,9,8]，[3,5,1,7,2,22,9,8]，[3,5,1,7， 2,22,9,8]，[3,5,1,7,2,22,9,8]，[3,5,1,7,2,22,9,8]，[3,5]， 1,7,2,22,9,8]，[3,5,1,7,2,22,9,8]] [[3,5,1,7,2,22,9,8,4]，[3,5,1,7,2,22,9,8,4]，[3,5,1,7， 2,22,9,8,4]，[3,5,1,7,2,22,9,8,4]，[3,5,1,7,2,22,9,8,4] ，[3,5,1,7,2,22,9,8,4]，[3,5,1,7,2,22,9,8,4]，[3,5,1,7， 2,22,9,8,4]，[3,5,1,7,2,22,9,8,4]，[3,5,1,7,2,22,9,8,4] ] [[3,5,1,7,2,22,9,8,4,11]，[3,5,1,7,2,22,9,8,4,11]，[3,5]， 1,7,2,22,9,8,4,11]，[3,5,1,7,2,22,9,8,4,11]，[3,5,1,7,2] 22,9,8,4,11]，[3,5,1,7,2,22,9,8,4,11]，[3,5,1,7,2,22,9,8， 4,11]，[3,5,1,7,2,22,9,8,4,11]，[3,5,1,7,2,22,9,8,4,11]，[ 3,5,1,7,2,22,9,8,4,11]]

Answer 1

这篇文章建议不要将其作为可变对象进行初始化：Append a new item to a list within a list

相反，将列表重写为：

>>> b=[[] for _ in xrange(10)]
>>> b
[[], [], [], [], [], [], [], [], [], []]
>>> b[0].append(0)
>>> b
[[0], [], [], [], [], [], [], [], [], []]

对于您提供的代码，

a=[3,5,1,7,2,22,9,8,4,11]
b=[[] for _ in xrange(10)]
d=10;
for i in range(len(a)):
    b[i].append(a[i])
    print b

输出：

[[3], [], [], [], [], [], [], [], [], []]
[[3], [5], [], [], [], [], [], [], [], []]
[[3], [5], [1], [], [], [], [], [], [], []]
[[3], [5], [1], [7], [], [], [], [], [], []]
[[3], [5], [1], [7], [2], [], [], [], [], []]
[[3], [5], [1], [7], [2], [22], [], [], [], []]
[[3], [5], [1], [7], [2], [22], [9], [], [], []]
[[3], [5], [1], [7], [2], [22], [9], [8], [], []]
[[3], [5], [1], [7], [2], [22], [9], [8], [4], []]
[[3], [5], [1], [7], [2], [22], [9], [8], [4], [11]]

在第i个列表中追加值

1 个答案: