from sklearn import datasets from sklearn.neighbors import KNeighborsClassifier from sklearn.model_selection import train_test_split import matplotlib.pyplot as plt import numpy as np # 加载数据集 iris = datasets.load_iris() X = iris.data y = iris.target # 划分训练集和测试集 X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.3) # 创建KNN分类器,K=3 knn = KNeighborsClassifier(n_neighbors=3) # 训练模型 knn.fit(X_train, y_train) # 在测试集上进行预测 y_pred = knn.predict(X_test) # 计算准确率 accuracy = knn.score(X_test, y_test) print("准确率为:", accuracy) # 绘制分类分布结果的二维图 colors = ['red', 'green', 'blue'] markers = ['o', 's', 'x'] for i, color, marker in zip(np.unique(y_pred), colors, markers): plt.scatter(X_test[y_pred == i, 0], X_test[y_pred == i, 1], color=color, marker=marker, label=iris.target_names[i]) plt.legend() plt.xlabel(iris.feature_names[0]) plt.ylabel(iris.feature_names[1]) plt.show()
时间: 2024-03-18 16:44:27 浏览: 19
这段代码使用了scikit-learn库中的K近邻算法实现对鸢尾花数据集的分类。首先,通过导入数据集并将其分为训练集和测试集。然后创建了一个KNeighborsClassifier对象,其中传递参数n_neighbors=3表示使用3个邻居来进行分类。接下来,使用fit()方法训练模型,使用predict()方法在测试集上进行预测。最后,使用score()方法计算模型在测试集上的准确率,并使用matplotlib库绘制了分类结果的二维图。
相关问题
在Python中想运行from sklearn.model_selection import train_test_split from sklearn.decomposition import PCA import pandas as pd from sklearn import svm import numpy as np import math import matplotlib.pyplot as plt import matplotlib as mpl from matplotlib import colors from sklearn.model_selection import train_test_split from sklearn import datasets from matplotlib.colors import ListedColormap from sklearn.svm import SVC from sklearn.preprocessing import StandardScaler from sklearn.model_selection import StratifiedShuffleSplit,StratifiedKFold from sklearn.model_selection import GridSearchCV from sklearn.model_selection import GridSearchCV, LeaveOneOut, cross_val_predict from sklearn.model_selection import KFold from sklearn.linear_model import LogisticRegression from sklearn.naive_bayes import GaussianNB from sklearn.neighbors import KNeighborsClassifier from sklearn import svm from sklearn.tree import DecisionTreeClassifier from sklearn.ensemble import RandomForestClassifier from sklearn.metrics import roc_auc_score from sklearn.metrics import roc_auc_score import math import datetime import multiprocessing as mp from sklearn.ensemble import StackingClassifier from sklearn.pipeline import make_pipeline from sklearn.svm import LinearSVC import random怎么操作
要在Python中运行这些代码,你需要确保已经安装了相应的包。大多数包都可以使用`pip`进行安装。
首先,在命令行中运行以下命令来安装所需的包:
```bash
pip install scikit-learn pandas matplotlib numpy
```
然后,在你的Python脚本中导入所需的库:
```python
from sklearn.model_selection import train_test_split
from sklearn.decomposition import PCA
import pandas as pd
from sklearn import svm
import numpy as np
import math
import matplotlib.pyplot as plt
import matplotlib as mpl
from matplotlib import colors
from sklearn.model_selection import train_test_split
from sklearn import datasets
from matplotlib.colors import ListedColormap
from sklearn.svm import SVC
from sklearn.preprocessing import StandardScaler
from sklearn.model_selection import StratifiedShuffleSplit, StratifiedKFold
from sklearn.model_selection import GridSearchCV
from sklearn.model_selection import GridSearchCV, LeaveOneOut, cross_val_predict
from sklearn.model_selection import KFold
from sklearn.linear_model import LogisticRegression
from sklearn.naive_bayes import GaussianNB
from sklearn.neighbors import KNeighborsClassifier
from sklearn.tree import DecisionTreeClassifier
from sklearn.ensemble import RandomForestClassifier
from sklearn.metrics import roc_auc_score
import datetime
import multiprocessing as mp
from sklearn.ensemble import StackingClassifier
from sklearn.pipeline import make_pipeline
from sklearn.svm import LinearSVC
import random
```
请确保在运行这些代码之前,已经安装了所需的Python库。如果遇到任何问题,请确保已正确安装这些库,并且版本与代码兼容。
优化这段代码# import modules 导入模块 from sklearn.model_selection import train_test_split from sklearn.decomposition import PCA import pandas as pd from sklearn import svm import numpy as np import math import matplotlib.pyplot as plt import matplotlib as mpl from matplotlib import colors from sklearn.model_selection import train_test_split from sklearn import datasets from matplotlib.colors import ListedColormap from sklearn.svm import SVC from sklearn.preprocessing import StandardScaler from sklearn.model_selection import StratifiedShuffleSplit,StratifiedKFold from sklearn.model_selection import GridSearchCV from sklearn.model_selection import GridSearchCV, LeaveOneOut, cross_val_predict from sklearn.model_selection import KFold from sklearn.linear_model import LogisticRegression from sklearn.naive_bayes import GaussianNB from sklearn.neighbors import KNeighborsClassifier from sklearn import svm from sklearn.tree import DecisionTreeClassifier from sklearn.ensemble import RandomForestClassifier from sklearn.metrics import roc_auc_score from sklearn.metrics import roc_auc_score import math import datetime import multiprocessing as mp from sklearn.ensemble import StackingClassifier from sklearn.pipeline import make_pipeline from sklearn.svm import LinearSVC import random
你可以对这段代码进行如下优化:
```python
import pandas as pd
import numpy as np
import math
import matplotlib.pyplot as plt
import matplotlib as mpl
from matplotlib import colors
from matplotlib.colors import ListedColormap
from sklearn.model_selection import train_test_split, StratifiedShuffleSplit, StratifiedKFold, GridSearchCV, LeaveOneOut, cross_val_predict, KFold
from sklearn.decomposition import PCA
from sklearn.svm import SVC, LinearSVC
from sklearn.preprocessing import StandardScaler
from sklearn.linear_model import LogisticRegression
from sklearn.naive_bayes import GaussianNB
from sklearn.neighbors import KNeighborsClassifier
from sklearn.tree import DecisionTreeClassifier
from sklearn.ensemble import RandomForestClassifier, StackingClassifier
from sklearn.metrics import roc_auc_score
# 导入模块
# 设置随机种子
random.seed(42)
np.random.seed(42)
# 其他代码...
```
这样做的优点是将导入的模块进行整理和分类,提高了代码的可读性。同时,设置了随机种子,保证了代码的可复现性。你可以根据需要添加其他的代码或模块。