我需要确定不同的分类模型预测值的能力。为了做到这一点，我需要绘制一个ROC曲线，但我正在努力开发一种方法。在
我包括了我的整个python代码以及到我使用的数据集的链接。它看起来有很多代码，但实际上很简单。我发现的主要问题是，我有一个3x3混淆矩阵，不知道如何将其转换成ROC图。在
非常感谢任何帮助。在
数据集：import pandas as pd
import matplotlib.pyplot as plt
from sklearn.metrics import confusion_matrix
from sklearn.utils.multiclass import unique_labels
import seaborn as sns
import numpy as np
#data = pd.read_csv('wineQualityReds.csv', usecols=lambda x: 'Unnamed' not in x,)
data = pd.read_csv('wineQualityWhites.csv', usecols=lambda x: 'Unnamed' not in x,)
# roc curve and auc score
from sklearn.datasets import make_classification
from sklearn.neighbors import KNeighborsClassifier
from sklearn.ensemble import RandomForestClassifier
from sklearn.model_selection import train_test_split
from sklearn.metrics import roc_curve
from sklearn.metrics import roc_auc_score
def plot_roc_curve(fpr, tpr):
plt.plot(fpr, tpr, color='orange', label='ROC')
plt.plot([0, 1], [0, 1], color='darkblue', linestyle='--')
plt.xlabel('False Positive Rate')
plt.ylabel('True Positive Rate')
plt.title('Receiver Operating Characteristic (ROC) Curve')
plt.legend()
plt.show()
bins = [1,4,6,10]
quality_labels = [0,1,2]
data['quality_categorial'] = pd.cut(data['quality'], bins = bins, labels = quality_labels, include_lowest = True)
display(data.head(n=2))
quality_raw = data['quality_categorial']
features_raw = data.drop(['quality', 'quality_categorial'], axis = 1)
from sklearn.model_selection import train_test_split
X_train, X_test, y_train, y_test = train_test_split(features_raw, quality_raw, test_size = 0.2, random_state = 0)
from sklearn.metrics import fbeta_score
from sklearn.metrics import accuracy_score
def train_predict_evaluate(learner, sample_size, X_train, y_train, X_test, y_test):
results = {}
#start = time()
learner = learner.fit(X_train[:sample_size], y_train[:sample_size])
#end = time()
#results['train_time'] = end - start
#start = time()
predictions_train = learner.predict(X_train[:300])
predictions_test = learner.predict(X_test)
#end = time()
#results['pred_time'] = end - start
results['acc_train'] = accuracy_score(y_train[:300], predictions_train)
results['acc_test'] = accuracy_score(y_test, predictions_test)
results['f_train'] = fbeta_score(y_train[:300], predictions_train, beta = 0.5, average = 'micro')
results['f_test'] = fbeta_score(y_test, predictions_test, beta = 0.5, average = 'micro')
#####################
#array = print(confusion_matrix(y_test, predictions_test))
labels = ['Positives','Negatives']
cm = confusion_matrix(y_test, predictions_test)
print(cm)
df_cm = pd.DataFrame(cm, columns=np.unique(y_test), index = np.unique(y_test))
df_cm.index.name = 'Actual'
df_cm.columns.name = 'Predicted'
plt.figure(figsize = (10,7))
sns.set(font_scale=1.4)#for label size
sns.heatmap(df_cm, cmap="Blues", annot=True, fmt = 'g',annot_kws={"size": 16})# font size
#######################
print(predictions_test)
#auc = roc_auc_score(y_test, probs)
#print('AUC: %.2f' % auc)
#fpr, tpr, thresholds = roc_curve(y_test, probs)
#plot_roc_curve(fpr, tpr)
print("{} trained on {} samples." .format(learner.__class__.__name__, sample_size))
return results
from sklearn.naive_bayes import GaussianNB
from sklearn.tree import DecisionTreeClassifier
from sklearn.ensemble import RandomForestClassifier
clf_A = GaussianNB()
clf_B = DecisionTreeClassifier(max_depth=None, random_state=None)
clf_C = RandomForestClassifier(max_depth=None, random_state=None)
samples_100 = len(y_train)
samples_10 = int(len(y_train)*10/100)
samples_1 = int(len(y_train)*1/100)
results = {}
for clf in [clf_A,clf_B,clf_C]:
clf_name = clf.__class__.__name__
results[clf_name] = {}
for i, samples in enumerate([samples_1, samples_10, samples_100]):
results[clf_name][i] = \
train_predict_evaluate(clf, samples, X_train, y_train, X_test, y_test)
train_predict_evaluate(clf_C, samples_100, X_train, y_train, X_test, y_test)