python - 过滤列表列的列表，然后在 Python 中逐行拆分(分解)

Question

假设我在具有列表列表的数据框中有一列:

   id                                                pos
0   1  [[['Malaysia','NR'], [':','PU'], ['Natural','JJ'], ['selling price','NN']]]
1   2  [[['Spot Price','NN'], [':','PU'], ['cotton','NN'], ['India', ' NR']]]

或字典格式:

[{'id': 1,
  'pos': "[[['Malaysia','NR'], [':','PU'], ['Natural','JJ'], ['selling price','NN']]]"},
 {'id': 2,
  'pos': "[[['Spot Price','NN'], [':','PU'], ['cotton','NN'], ['India', ' NR']]]"}]

如果列表的第二个元素是 NR，我该如何过滤或 NN然后 split (爆炸)pos按行列如下:

   id          words part_of_speech
0   1        Malasia             NR
1   1  selling price             NN
2   2     Spot price             NN
3   2         cotton             NN
4   2          India             NR

我怎么能在 Python 中做到这一点？谢谢。
试用代码:

l = [[['Malaysia','NR'], [':','PU'], ['Natural','JJ'], ['selling price','NN']]]
for elem in l[0]:
    print(elem[1])

出去:

NR
PU
JJ
NN

Answer 1

你可以用 explode 试试这个:

x = df.explode('pos').explode('pos')
x = x[['id']].reset_index(drop=True).join(pd.DataFrame(x['pos'].tolist()).set_axis(['words', 'part_of_speech'], axis=1))
x.loc[x['part_of_speech'].isin(['NN', 'NR'])]

   id          words part_of_speech
0   1       Malaysia             NR
3   1  selling price             NN
4   2     Spot Price             NN
6   2         cotton             NN
7   2          India             NR
>>> 

对于具有任意长度的数据帧，此解决方案可以轻松缩放，它不会一一分配列，而是一次分配列。所以它适用于任意长度的子列表。