我想可视化我从带有熊猫的CSV文件创建的DataFrame用于学校作业。 DataFrame包含有关来自两个不同书章的句子的数据。我想从一本书的特定章节中提取数据，并创建两个新的单独的DataFrame。因此，我试图访问“章”列中所有包含“ 1”的行（如第1章中所述）。 数据框如下所示：
length sentences chapter ranking
0 99 The word "house" is not a linguistic fact if b... 1 1
1 201 In an age when the study of antiquity attracte... 2 1
2 88 This can only mean that the sounds of speech a... 1 2
3 145 If you consider that whatever view we take of ... 2 2
4 75 If the involuntary cry of pain which is conven... 1 3
5 136 For it is evident we observe no footsteps in t... 2 3
6 71 The auditory centers alone may be excited; or ... 1 4
7 118 Man had studied every part of nature the miner... 2 4
8 68 The auditory symbolism may be replaced point f... 1 5
9 116 It has absorbed the thoughts of men who after ... 2 5
10 68 These symbols are in the first instance audito... 1 6
11 93 The dimensions of the science of language are ... 2 6
12 68 Naturally the particular points or clusters of... 1 7
13 91 The astronomer retains these and many other na... 2 7
14 66 It is even conceivable if not exactly likely t... 1 8
15 92 Lord Monboddo for instance admits that as yet ... 2 8
16 65 As such they may be considered an integral por... 1 9
17 89 It is counted as a science by so sound and sob... 2 9
18 63 If language can be said to be definitely "loca... 1 10
19 86 If with all these difficulties and drawbacks I... 2 10
我尝试使用此代码选择所需的行，并将其分配给新变量（chapter1）：
df = pd.read_csv('task1.csv')
chapter1 = df[df.chapter == '1']
我想为这些行创建一个新的数据框。我收到错误消息： 逐元素比较失败；而是返回标量，但将来会执行逐元素比较
如何解决此错误？
感谢所有帮助