python - 如何将每组中的行从第一行切片到包含特定值的行？

Question

我有一个这样的数据框:

df_1 = pd.DataFrame({
    'ID' : ['A', 'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', 'C', 'C', 'C', 'C', 'C'],
    'VAL' : ['shoes', 'flowers', 'chairs', 'apples', 'dice', 'shoes', 'apples',
             'curtain', 'sand', 'socks', 'necklacs', 'tables', 'dishes', 'apples'],
    'SEQ' : [0, 1, 2, 3, 4, 0, 1, 2, 3, 0, 1, 2, 3, 4]
})

   ID       VAL  SEQ
0   A     shoes    0
1   A   flowers    1
2   A    chairs    2
3   A    apples    3
4   A      dice    4
5   B     shoes    0
6   B    apples    1
7   B   curtain    2
8   B      sand    3
9   C     socks    0
10  C  necklacs    1
11  C    tables    2
12  C    dishes    3
13  C    apples    4

我想对直到一个值的行进行切片，例如，对每个 ID 组中的所有行进行切片，直到 apple:

Out[110]: 
   ID       VAL  SEQ
0   A     shoes    0
1   A   flowers    1
2   A    chairs    2
3   A    apples    3
4   B     shoes    0
5   B    apples    1
6   C     socks    0
7   C  necklacs    1
8   C    tables    2
9   C    dishes    3
10  C    apples    4

Answer 1

idxmax、groupby、concat

pd.concat([
    d.loc[:d.VAL.eq('apples').idxmax()]
    for _, d in df_1.groupby('ID')
])

   ID       VAL  SEQ
0   A     shoes    0
1   A   flowers    1
2   A    chairs    2
3   A    apples    3
5   B     shoes    0
6   B    apples    1
9   C     socks    0
10  C  necklacs    1
11  C    tables    2
12  C    dishes    3
13  C    apples    4