获取 SelectKBest 函数的特征名称 python

Question

我从 sklearn 实现了 SelectKBest，我想获得 K 个最佳列的名称，而不仅仅是每个列的值。

我需要做什么？

我的代码：

X_new = SelectKBest(chi2, k=2).fit_transform(X, y)

X_new.shape

X_new 是一个 numpy.ndarray 并且它有 k col 但没有 col 名称。

Answer 1

model=SelectKBest(k=5) model.fit(X,y)

print(model.get_params)

Answer 2

您可以获得所选特征的索引。

示例 1:

from sklearn.datasets import load_iris
from sklearn.feature_selection import SelectKBest
from sklearn.feature_selection import chi2

iris = load_iris()
X, y = iris.data, iris.target

selector = SelectKBest(chi2, k=2)
selector.fit(X, y)

X_new = selector.transform(X)
X_new.shape
print(selector.get_support(indices=True))

现在如果你真的想得到我们需要使用的列的实际名称pandas。

示例 2:

from sklearn.datasets import load_iris
from sklearn.feature_selection import SelectKBest
from sklearn.feature_selection import chi2
import pandas as pd

iris = load_iris()
X = pd.DataFrame(iris.data, columns=iris.feature_names)
y = pd.DataFrame(iris.target)

selector = SelectKBest(chi2, k=2)
selector.fit(X, y)

X_new = selector.transform(X)
print(X_new.shape)

X.columns[selector.get_support(indices=True)]

# 1st way to get the list
vector_names = list(X.columns[selector.get_support(indices=True)])
print(vector_names)

#2nd way
X.columns[selector.get_support(indices=True)].tolist()

结果：

Index([u'petal length (cm)', u'petal width (cm)'], dtype='object')

['petal length (cm)', 'petal width (cm)']

['petal length (cm)', 'petal width (cm)']

Answer 3

model=SelectKBest(f_classif, k=8).fit(X,Y)

Selected_feature_names=X.columns[model.get_support()]

获取 SelectKBest 函数的特征名称 python

get feature names of SelectKBest function python

python

selection