NameError Traceback (most recent call last)<ipython-input-15-aab8952af4eb> in <module>()----> 1 plot_decision_regions(X, y, classifier, resolution=0.02)NameError: name 'classifier' is not defined
NameError Traceback (most recent call last)<ipython-input-15-aab8952af4eb> in <module>()----> 1 plot_decision_regions(X, y, classifier, resolution=0.02)NameError: name 'classifier' is not defined
2018-01-28
你看一下代码，照着改一下，应该就能解决。
from matplotlib.colors import ListedColormap
def plot_decision_regions(X, y, classifier, resolution=0.02):
marker = ('s', 'x', 'o', 'v')
colors = ('red', 'blue', 'lightgreen', 'gray', 'cyan')
cmap = ListedColormap(colors[:len(np.unique(y))])
x1_min, x1_max = X[:, 0].min() - 1, X[:, 0].max()
x2_min, x2_max = X[:, 1].min() - 1, X[:, 1].max()
#将x1、x2最大最小值通过arange函数得到的向量，扩展成两个二维矩阵
xx1, xx2 = np.meshgrid(np.arange(x1_min, x1_max, resolution), np.arange(x2_min, x2_max, resolution))
#预测
Z = classifier.predict(np.array([xx1.ravel(), xx2.ravel()]).T) #ravel还原成单维向量
#绘制
Z= Z.reshape(xx1.shape) #将Z转换成与xx1一样的二维数组
plt.contourf(xx1, xx2, Z, alpha=0.4, cmap=cmap) #在两组分类结果中间画分割线-->必须线性可分
plt.xlim(xx1.min(), xx1.max())
plt.ylim(xx2.min(), xx2.max())
for idx, cl in enumerate(np.unique(y)):
plt.scatter(x=X[y==cl, 0], y=X[y==cl, 1], alpha=0.8, c=cmap(idx), marker=marker[idx], label=cl)
ppn = Perceptron(0.1, 10)
ppn.fit(X, y)
plot_decision_regions(X, y, ppn, resolution=0.02)举报
