Note
Go to the end to download the full example code. or to run this example in your browser via Binder
显示流水线#
在 Jupyter Notebook 中显示流水线的默认配置是 'diagram' ，即 set_config(display='diagram') 。要停用 HTML 表示形式，请使用 set_config(display='text') 。
要在流水线的可视化中查看更详细的步骤，请点击流水线中的步骤。
显示包含预处理步骤和分类器的管道
本节构建了一个包含预处理步骤 StandardScaler 和分类器 LogisticRegression 的 Pipeline ，并展示其可视化表示。
from sklearn import set_config
from sklearn.linear_model import LogisticRegression
from sklearn.pipeline import Pipeline
from sklearn.preprocessing import StandardScaler
steps = [
("preprocessing", StandardScaler()),
("classifier", LogisticRegression()),
]
pipe = Pipeline(steps)
要可视化图表，默认设置为 display='diagram' 。
set_config(display="diagram")
pipe # click on the diagram below to see the details of each step
要查看文本管道，请更改为 display='text' 。
set_config(display="text")
pipe
Pipeline(steps=[('preprocessing', StandardScaler()),
('classifier', LogisticRegression())])
恢复默认显示
set_config(display="diagram")
显示一个包含多个预处理步骤和分类器的管道
本节构建了一个包含多个预处理步骤的 Pipeline ，包括 PolynomialFeatures 和 StandardScaler ，以及一个分类器步骤 LogisticRegression ，并显示其可视化表示。
from sklearn.linear_model import LogisticRegression
from sklearn.pipeline import Pipeline
from sklearn.preprocessing import PolynomialFeatures, StandardScaler
steps = [
("standard_scaler", StandardScaler()),
("polynomial", PolynomialFeatures(degree=3)),
("classifier", LogisticRegression(C=2.0)),
]
pipe = Pipeline(steps)
pipe # click on the diagram below to see the details of each step
显示管道、降维和分类器
本节构建了一个包含降维步骤 PCA 和分类器 SVC 的 Pipeline ，并展示其可视化表示。
显示一个复杂的管道链列转换器
本节构建了一个复杂的 Pipeline ，其中包含一个 ColumnTransformer 和一个分类器 LogisticRegression ，并展示其可视化表示。
import numpy as np
from sklearn.compose import ColumnTransformer
from sklearn.impute import SimpleImputer
from sklearn.linear_model import LogisticRegression
from sklearn.pipeline import Pipeline, make_pipeline
from sklearn.preprocessing import OneHotEncoder, StandardScaler
numeric_preprocessor = Pipeline(
steps=[
("imputation_mean", SimpleImputer(missing_values=np.nan, strategy="mean")),
("scaler", StandardScaler()),
]
)
categorical_preprocessor = Pipeline(
steps=[
(
"imputation_constant",
SimpleImputer(fill_value="missing", strategy="constant"),
),
("onehot", OneHotEncoder(handle_unknown="ignore")),
]
)
preprocessor = ColumnTransformer(
[
("categorical", categorical_preprocessor, ["state", "gender"]),
("numerical", numeric_preprocessor, ["age", "weight"]),
]
)
pipe = make_pipeline(preprocessor, LogisticRegression(max_iter=500))
pipe # click on the diagram below to see the details of each step
展示一个包含分类器的管道的网格搜索#
本节构建了一个包含
RandomForestClassifier的Pipeline上的GridSearchCV，并显示其可视化表示。
import numpy as np
from sklearn.compose import ColumnTransformer
from sklearn.ensemble import RandomForestClassifier
from sklearn.impute import SimpleImputer
from sklearn.model_selection import GridSearchCV
from sklearn.pipeline import Pipeline, make_pipeline
from sklearn.preprocessing import OneHotEncoder, StandardScaler
numeric_preprocessor = Pipeline(
steps=[
("imputation_mean", SimpleImputer(missing_values=np.nan, strategy="mean")),
("scaler", StandardScaler()),
]
)
categorical_preprocessor = Pipeline(
steps=[
(
"imputation_constant",
SimpleImputer(fill_value="missing", strategy="constant"),
),
("onehot", OneHotEncoder(handle_unknown="ignore")),
]
)
preprocessor = ColumnTransformer(
[
("categorical", categorical_preprocessor, ["state", "gender"]),
("numerical", numeric_preprocessor, ["age", "weight"]),
]
)
pipe = Pipeline(
steps=[("preprocessor", preprocessor), ("classifier", RandomForestClassifier())]
)
param_grid = {
"classifier__n_estimators": [200, 500],
"classifier__max_features": ["auto", "sqrt", "log2"],
"classifier__max_depth": [4, 5, 6, 7, 8],
"classifier__criterion": ["gini", "entropy"],
}
grid_search = GridSearchCV(pipe, param_grid=param_grid, n_jobs=1)
grid_search # click on the diagram below to see the details of each step
Total running time of the script: (0 minutes 0.045 seconds)
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