使用 shap 包获取数据框中要素的瀑布图值

Question

我正在使用随机森林模型和神经网络进行二元分类，其中使用 SHAP 来解释模型预测。我跟着教程写了下面的代码来得到下面显示的瀑布图

在 Sergey Bushmanaov 的 SO post here 的帮助下，我成功地将瀑布图导出到数据框。但这不会复制列的特征值。它只复制形状值、expected_value 和特征名称。但我也想要功能名称。所以，我尝试了以下

shap.waterfall_plot(shap.Explanation(values=shap_values[1])[4],base_values=explainer.expected_value[1],data=ord_test_t.iloc[4],feature_names=ord_test_t.columns.tolist())

但这引发了错误

TypeError: waterfall() got an unexpected keyword argument 'base_values'

我希望我的输出如下所示。我使用 1 点的背景来计算基值。但您也可以自由使用背景 1,10 或 100。在下面的输出中，我将值和特征存储在一个名为 Feature 的列中。这类似于 LIME。但不确定 SHAP 是否具有执行此操作的灵活性？

更新-情节

更新代码 - 内核解释器瀑布到数据帧

masker = Independent(X_train, max_samples=100)
explainer = KernelExplainer(rf_boruta.predict,X_train)
bv = explainer.expected_value
sv = explainer.shap_values(X_train)

sdf_train = pd.DataFrame({
    'row_id': X_train.index.values.repeat(X_train.shape[1]),
    'feature': X_train.columns.to_list() * X_train.shape[0],
    'feature_value': X_train.values.flatten(),
    'base_value': bv,
    'shap_values': sv.values[:,:,1].flatten()   # i changed this to pd.DataFrame(sv).values[:,1].flatten()
})

Answer 1

尝试以下操作：

from sklearn.ensemble import RandomForestClassifier
from sklearn.datasets import load_breast_cancer
from shap import TreeExplainer, Explanation
from shap.plots import waterfall

import shap
print(shap.__version__)

X, y = load_breast_cancer(return_X_y=True, as_frame=True)
model = RandomForestClassifier(max_depth=5, n_estimators=100).fit(X, y)
explainer = TreeExplainer(model)
sv = explainer(X)
exp = Explanation(sv.values[:,:,1], 
                  sv.base_values[:,1], 
                  data=X.values, 
                  feature_names=X.columns)
idx = 0
waterfall(exp[idx])

0.39.0

然后：

pd.DataFrame({
    'row_id':idx,
    'feature': X.columns,
    'feature_value': exp[idx].values,
    'base_value': exp[idx].base_values,
    'shap_values': exp[idx].values
})

#expected output
row_id  feature feature_value   base_value  shap_values
0   0   mean radius -0.035453   0.628998    -0.035453
1   0   mean texture    0.047571    0.628998    0.047571
2   0   mean perimeter  -0.036218   0.628998    -0.036218
3   0   mean area   -0.041276   0.628998    -0.041276
4   0   mean smoothness -0.006842   0.628998    -0.006842
5   0   mean compactness    -0.009275   0.628998    -0.009275
6   0   mean concavity  -0.035188   0.628998    -0.035188
7   0   mean concave points -0.051165   0.628998    -0.051165
8   0   mean symmetry   -0.002192   0.628998    -0.002192
9   0   mean fractal dimension  0.001521    0.628998    0.001521
10  0   radius error    -0.021223   0.628998    -0.021223
11  0   texture error   -0.000470   0.628998    -0.000470
12  0   perimeter error -0.021423   0.628998    -0.021423
13  0   area error  -0.035313   0.628998    -0.035313
14  0   smoothness error    -0.000060   0.628998    -0.000060
15  0   compactness error   0.001053    0.628998    0.001053
16  0   concavity error -0.002988   0.628998    -0.002988
17  0   concave points error    0.000140    0.628998    0.000140
18  0   symmetry error  0.001238    0.628998    0.001238
19  0   fractal dimension error -0.001097   0.628998    -0.001097
20  0   worst radius    -0.050027   0.628998    -0.050027
21  0   worst texture   0.038056    0.628998    0.038056
22  0   worst perimeter -0.079717   0.628998    -0.079717
23  0   worst area  -0.072312   0.628998    -0.072312
24  0   worst smoothness    -0.006917   0.628998    -0.006917
25  0   worst compactness   -0.016184   0.628998    -0.016184
26  0   worst concavity -0.022500   0.628998    -0.022500
27  0   worst concave points    -0.088697   0.628998    -0.088697
28  0   worst symmetry  -0.026166   0.628998    -0.026166
29  0   worst fractal dimension -0.007683   0.628998    -0.007683

RandomForest有点特殊，是这个原因。当新地块 API 出现问题时，请尝试提供 Explanation 对象。

更新

解释 1 class 数据点与单个 0 背景数据点：

back_id = 10
exp_id = 20
explainer = TreeExplainer(model, data=X.loc[[back_id]])
sv = explainer(X.loc[[exp_id]])
exp = Explanation(sv.values[:,:,1], sv.base_values[:,1], data=X.loc[[back_id]].values, feature_names=X.columns)
waterfall(exp[0])

最后，正如您要求的所有内容都采用建议的格式：

from shap.maskers import Independent
from sklearn.model_selection import train_test_split

X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=42)

model = RandomForestClassifier(max_depth=5, n_estimators=100).fit(X_train, y_train)

masker = Independent(X_train, max_samples=100)
explainer = TreeExplainer(model, data=masker)
bv = explainer.expected_value[1]
sv = explainer(X_test, check_additivity=False)

pd.DataFrame({
    'row_id': X_test.index.values.repeat(X_test.shape[1]),
    'feature': X_test.columns.to_list() * X_test.shape[0],
    'feature_value': X_test.values.flatten(),
    'base_value': bv,
    'shap_values': sv.values[:,:,1].flatten()
})

但我绝对不会给我妈妈看这个。

使用 shap 包获取数据框中要素的瀑布图值

Get waterfall plot values of a feature in a dataframe using shap package

python

classification

machine-learning

random-forest

shap