要列出的 Pandas DataFrame 列值
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Pandas DataFrame column values in to list
提问by Nilani Algiriyage
I have a pandas DataFramelike following
我有一只DataFrame像下面这样的Pandas
clusters
0 [4]
1 [9, 14, 16, 19]
2 [6, 7, 10, 17, 18, 20]
3 [1, 2, 3, 5, 8, 11, 12, 13, 15]
I need to get only the integer values in the cluster column separately. Like following(This can be four lists no need of having another DataFrame)
我只需要分别获取簇列中的整数值。喜欢以下（这可以是四个列表，不需要另一个DataFrame）
0 4
1 9, 14, 16, 19
2 6, 7, 10, 17, 18, 20
3 1, 2, 3, 5, 8, 11, 12, 13, 15
I tried different things. Could not achieve the expected output.
我尝试了不同的东西。无法达到预期的输出。
In [36]: clustlist = list(firstclusters.clusters.values)
Out[36]:
[array([4]), array([ 9, 14, 16, 19]), array([ 6, 7, 10, 17, 18, 20]), array([ 1, 2, 3, 5, 8, 11, 12, 13, 15])]
In [37]: np.ravel(clustlist)
Out[37]:
[array([4]) array([ 9, 14, 16, 19]) array([ 6, 7, 10, 17, 18, 20])
array([ 1, 2, 3, 5, 8, 11, 12, 13, 15])]
In [38]: np.hstack(clustlist)
Out[38]:
[ 4 9 14 16 19 6 7 10 17 18 20 1 2 3 5 8 11 12 13 15]
回答by Andy Hayden
If each item is just a list, you can use the tolist Series method:
如果每个项目只是一个列表，则可以使用 tolist Series 方法：
In [11]: df.clusters.tolist()
Out[11]: [[4], [9, 14, 16, 19], [6, 7, 10, 17, 18, 20], [1, 2, 3, 5, 8, 11, 12, 13, 15]]
Or, if these are numpy arrays you need to apply tolist to each item first:
或者，如果这些是 numpy 数组，您需要先将 tolist 应用于每个项目：
In [12]: df.clusters.apply(np.ndarray.tolist).tolist()
Out[12]: [[4], [9, 14, 16, 19], [6, 7, 10, 17, 18, 20], [1, 2, 3, 5, 8, 11, 12, 13, 15]]
