如何将python列表附加到包含数组的每个数据帧单元？

我的代码：

df=pd.DataFrame(columns=["a","b"], index=np.arange(1,3))
for col in df.columns:
  df[col].values[:]=[[]*2]
print(df)
for col,n in enumerate(df.columns):
  for row in range(1,3):
    df[n][row].append([1,2,3])
    print(df)

           a   b
1  []  []
2  []  []
0 a
             a   b
1  [[1, 2, 3]]  []
2  [[1, 2, 3]]  []
0 a
                        a   b
1  [[1, 2, 3], [1, 2, 3]]  []
2  [[1, 2, 3], [1, 2, 3]]  []
1 b
                        a            b
1  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3]]
2  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3]]
1 b
                        a                       b
1  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3], [1, 2, 3]]
2  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3], [1, 2, 3]]
   

    a       b
1   []     []
2   []     []
0 a
         a    b
1   [[1,2,3]] []
2       []    []
0 a
         a    b
1   [[1,2,3]] []
2   [[1,2,3]] []
1 b
         a         b
1   [[1,2,3]]  [[1,2,3]]
2   [[1,2,3]]  []
1 b
         a         b
1   [[1,2,3]]  [[1,2,3]]
2   [[1,2,3]]  [[1,2,3]]

输出：

df=pd.DataFrame(columns=["a","b"], index=np.arange(1,3))
for col in df.columns:
  df[col].values[:]=[[]*2]
print(df)
for col,n in enumerate(df.columns):
  for row in range(1,3):
    df[n][row].append([1,2,3])
    print(df)

           a   b
1  []  []
2  []  []
0 a
             a   b
1  [[1, 2, 3]]  []
2  [[1, 2, 3]]  []
0 a
                        a   b
1  [[1, 2, 3], [1, 2, 3]]  []
2  [[1, 2, 3], [1, 2, 3]]  []
1 b
                        a            b
1  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3]]
2  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3]]
1 b
                        a                       b
1  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3], [1, 2, 3]]
2  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3], [1, 2, 3]]
   

    a       b
1   []     []
2   []     []
0 a
         a    b
1   [[1,2,3]] []
2       []    []
0 a
         a    b
1   [[1,2,3]] []
2   [[1,2,3]] []
1 b
         a         b
1   [[1,2,3]]  [[1,2,3]]
2   [[1,2,3]]  []
1 b
         a         b
1   [[1,2,3]]  [[1,2,3]]
2   [[1,2,3]]  [[1,2,3]]

我希望将输出作为列表添加到所有单元格中。但是列表不是添加到单元格中，而是添加到列的每一行中。请帮忙。先谢谢你

建议输出：

df=pd.DataFrame(columns=["a","b"], index=np.arange(1,3))
for col in df.columns:
  df[col].values[:]=[[]*2]
print(df)
for col,n in enumerate(df.columns):
  for row in range(1,3):
    df[n][row].append([1,2,3])
    print(df)

           a   b
1  []  []
2  []  []
0 a
             a   b
1  [[1, 2, 3]]  []
2  [[1, 2, 3]]  []
0 a
                        a   b
1  [[1, 2, 3], [1, 2, 3]]  []
2  [[1, 2, 3], [1, 2, 3]]  []
1 b
                        a            b
1  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3]]
2  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3]]
1 b
                        a                       b
1  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3], [1, 2, 3]]
2  [[1, 2, 3], [1, 2, 3]]  [[1, 2, 3], [1, 2, 3]]
   

    a       b
1   []     []
2   []     []
0 a
         a    b
1   [[1,2,3]] []
2       []    []
0 a
         a    b
1   [[1,2,3]] []
2   [[1,2,3]] []
1 b
         a         b
1   [[1,2,3]]  [[1,2,3]]
2   [[1,2,3]]  []
1 b
         a         b
1   [[1,2,3]]  [[1,2,3]]
2   [[1,2,3]]  [[1,2,3]]

---

在Python中，执行

[[[]*2]

实际上并没有像您可能期望的那样产生

[[]]，[]]

，而是

[[[]]

。当您执行

df[col].values[：]=[[[]*2]

时，实际上是将列

col

中的所有行设置为同一个列表。您可以这样检查：

df = pd.DataFrame(columns=["a","b"], index=np.arange(1,3))
df["a"].values[:] = [[] * 2]
df["a"][1].append([1,2,3])
print(df)

执行上述操作后，

df

将变为如下所示，因为您实际上同时修改了两行：

             a    b
1  [[1, 2, 3]]  NaN
2  [[1, 2, 3]]  NaN

---

您要做的是：

for col in df.columns:
    for row in df.index:
        df[col][row] = []

然后

---

（还请注意，我没有使用

enumerate（df.columns）

，因为我们不需要它，而是用

df.index
替换了
range（1,3）
）
你能显示预期的输出吗？我已经编辑了问题，包括建议的输出。请看一看。非常感谢。