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<p>我有这样一个数据帧:</p>
<pre><code>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
</code></pre>
<p>我想切片到某个值的行,例如,切片到<code>ID</code>的每个<code>apple</code>组的所有行:</p>
<pre><code>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
</code></pre>