这是我数据框的fin.Factory列，我的目标是仅具有实际观察值，消除空白行
0 chittagong asian apparels ltd
1 divine textile ltd (unit 2)
2 elite garments
3 fashion asia ltd
4 fortune apparels ltd
5 glory fashion wear ltd
6 hams fashion ltd
7 hams garments
8 hams washing & dyeing ltd
9 kattali textile ltd
10 fashion (miles + 1)
11 kwun tong apparels ltd
12 lenny apparels ltd
13 lenny fashions ltd
14 meghna knit composite ltd
15 miles fabrics ltd
16 mohar asian apparels ltd
17 multifabs ltd
18 northern corporation limited
19 northern garment
20 orchid garments ltd
21 printers & printers ltd
22 rabab fashion ind ltd
23 sepal garments ltd
24 sepal washing plant ltd
25 shams style - standard
26 shams style - sitches
27 stylecraft ltd
28 tm garment
29 tm textiles
30 tosrifa industries ltd
31 univogue 1
32 univogue 4
33 univogue garments co ltd (unit 2)
34 univogue garments co ltd (unit 3)
35 world ye apparels
36 akh fashions ltd
37 akh eco apparels ltd
38 akh knitting & dying ltd
39 energypac fashions ltd
40 clifton textiles and apparels
41 alpha clothing ltd
42 bangladesh spinners and knitters
43 bando design
44 liberty knitwear ltd (1)
45 midland knitwear ltd
46 micro fibre ltd
47 a-one polar ltd
48 liberty knitwear ltd (2)
49 geebee 1
50 geebee 2
51 continental
52 tcel (3 units)
53 transworld sweater ltd
54 youngones ii
55 cordial design
57 NaN
58 NaN
我拼命试图摆脱带有nan值的行，但我不明白为什么下面的代码现在可以正常工作
fin = fin[fin.Factory != np.NaN]