NameError：未定义名称'labels'

Question

我正在使用Python（Richart，Pedro Coelho）书中的Building Machine Learning Systems的逐行示例。

进口虹膜数据集后，我们希望与Setosa

data = load_iris() 
features = data['data'] 
plength = features[:, 2] 
# use numpy operations to get setosa features 
is_setosa = (labels == 'setosa') 

提取那些我得到这个

>>> is_setosa = (labels == 'setosa') 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
NameError: name 'labels' is not defined 

我想这是错字，所以我尝试

>>> is_setosa = plenght(labels == 'setosa') 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
NameError: name 'plenght' is not defined 
>>> is_setosa = plength(labels == 'setosa') 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
NameError: name 'labels' is not defined 
>>> is_setosa = data(labels == 'setosa') 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
NameError: name 'labels' is not defined 

什么我现在应该做什么？ 如何检查数据对象？

>>> data.labels 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
    File "/home/milenko/miniconda2/lib/python2.7/site-packages/sklearn/datasets/base.py", line 58, in __getattr__ 
    raise AttributeError(key) 
AttributeError: labels 
>>> data.dtypes 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
    File "/home/milenko/miniconda2/lib/python2.7/site-packages/sklearn/datasets/base.py", line 58, in __getattr__ 
    raise AttributeError(key) 
AttributeError: dtypes 

这是描述

- class:\n    - Iris-Setosa\n    - Iris-Versicolour\n    - Iris-Virginica\n : 

Answer 1

如果你只需要输入data到IPython的控制台，您将看到数据集的描述的相关部分。特别是有两个字段：data['target']包含与data['target_names']中报告的名称对应的数字标签{0,1,2}，即{'setosa'，'versicolor'，'virginica'}。

所以，你也许可以定义labels如下：

labels = map(lambda x: dict(enumerate(data['target_names']))[x], data['target']) 

Answer 2

它主要在东阳书中的代码是没有定义“标签”的。根据上下文，添加以下代码：

target = data['target'] 
target_names = data['target_names'] 
labels=np.array([target_names[i] for i in target])