```python from sklearn.datasets import loadiris from sklearn.modelselection import traintestsplit from sklearn.ensemble import RandomForestClassifier
加载数据
iris = load_iris() X = iris.data y = iris.target
划分训练集和测试集
Xtrain, Xtest, ytrain, ytest = traintestsplit(X, y, testsize=0.2, randomstate=42)
选择算法
clf = RandomForestClassifier()
训练模子
clf.fit(Xtrain, ytrain)
预测
ypred = clf.predict(Xtest) ```
4.3.2 模子训练
```python from sklearn.datasets import loadiris from sklearn.modelselection import traintestsplit from sklearn.ensemble import RandomForestClassifier
加载数据
iris = load_iris() X = iris.data y = iris.target
划分训练集和测试集
Xtrain, Xtest, ytrain, ytest = traintestsplit(X, y, testsize=0.2, randomstate=42)
选择算法
clf = RandomForestClassifier()
训练模子
clf.fit(Xtrain, ytrain)
预测
ypred = clf.predict(Xtest) ```
4.3.3 预测评估
```python from sklearn.datasets import loadiris from sklearn.modelselection import traintestsplit from sklearn.ensemble import RandomForestClassifier from sklearn.metrics import accuracy_score
加载数据
iris = load_iris() X = iris.data y = iris.target
划分训练集和测试集
Xtrain, Xtest, ytrain, ytest = traintestsplit(X, y, testsize=0.2, randomstate=42)
选择算法