1、简单（源码）：
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from itertools import cycle
from sklearn import svm, datasets
from sklearn.metrics import roc_curve, auc
from sklearn.model_selection import train_test_split
from sklearn.preprocessing import label_binarize
from sklearn.multiclass import OneVsRestClassifier
from scipy import interp
# Import some data to play with
iris = datasets.load_iris()
X = iris.data
y = iris.target
# Binarize the output
y = label_binarize(y, classes=[0, 1, 2])
n_classes = y.shape[1]
# Add noisy features to make the problem harder
random_state = np.random.RandomState(0)
n_samples, n_features = X.shape
X = np.c_[X, random_state.randn(n_samples, 200 * n_features)]
# shuffle and split training and test sets
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=.5,
random_state=0)
# Learn to predict each class against the other
classifier = OneVsRestClassifier(svm.SVC(kernel='linear', probability=True,
random_state=random_state))
y_score = classifier.fit(X_train, y_train).decision_function(X_test)
# Compute ROC curve and ROC area for each class
fpr = dict()
tpr = dict()
roc_auc = dict()
for i in range(n_classes):
fpr[i], tpr[i], _ = roc_curve(y_test[:, i], y_score[:, i])
roc_auc[i] = auc(fpr[i], tpr[i])
# Compute micro-average ROC curve and ROC area
fpr["micro"], tpr["micro"], _ = roc_curve(y_test.ravel(), y_score.ravel())
roc_auc["micro"] = auc(fpr["micro"], tpr["micro"])
#Plot of a ROC curve for a specific class
plt.figure()
lw = 2
plt.plot(fpr[2], tpr[2], color='darkorange',
lw=lw, label='ROC curve (area = %0.2f)' % roc_auc[2])
plt.plot([0, 1], [0, 1], color='navy', lw=lw, linestyle='--')
plt.xlim([0.0, 1.0])
plt.ylim([0.0, 1.05])
plt.xlabel('False Positive Rate')
plt.ylabel('True Positive Rate')
plt.title('Receiver operating characteristic example')
plt.legend(loc="lower right")
plt.show()
2、复杂（源码）：
print(__doc__)
import numpy as np from scipy import interp import matplotlib.pyplot as plt from itertools import cycle from sklearn import svm, datasets from sklearn.metrics import roc_curve, auc from sklearn.model_selection import StratifiedKFold # ############################################################################# # Data IO and generation # Import some data to play with iris = datasets.load_iris() X = iris.data y = iris.target X, y = X[y != 2], y[y != 2] n_samples, n_features = X.shape # Add noisy features random_state = np.random.RandomState(0) X = np.c_[X, random_state.randn(n_samples, 200 * n_features)] # ############################################################################# # Classification and ROC analysis # Run classifier with cross-validation and plot ROC curves cv = StratifiedKFold(n_splits=6) classifier = svm.SVC(kernel='linear', probability=True, random_state=random_state) tprs = [] aucs = [] mean_fpr = np.linspace(0, 1, 100) i = 0 for train, test in cv.split(X, y): probas_ = classifier.fit(X[train], y[train]).predict_proba(X[test]) # Compute ROC curve and area the curve fpr, tpr, thresholds = roc_curve(y[test], probas_[:, 1]) tprs.append(interp(mean_fpr, fpr, tpr)) tprs[-1][0] = 0.0 roc_auc = auc(fpr, tpr) aucs.append(roc_auc) plt.plot(fpr, tpr, lw=1, alpha=0.3, label='ROC fold %d (AUC = %0.2f)' % (i, roc_auc)) i += 1 plt.plot([0, 1], [0, 1], linestyle='--', lw=2, color='r', label='Chance', alpha=.8) mean_tpr = np.mean(tprs, axis=0) mean_tpr[-1] = 1.0 mean_auc = auc(mean_fpr, mean_tpr) std_auc = np.std(aucs) plt.plot(mean_fpr, mean_tpr, color='b', label=r'Mean ROC (AUC = %0.2f $\pm$ %0.2f)' % (mean_auc, std_auc), lw=2, alpha=.8) std_tpr = np.std(tprs, axis=0) tprs_upper = np.minimum(mean_tpr + std_tpr, 1) tprs_lower = np.maximum(mean_tpr - std_tpr, 0) plt.fill_between(mean_fpr, tprs_lower, tprs_upper, color='grey', alpha=.2, label=r'$\pm$ 1 std. dev.') plt.xlim([-0.05, 1.05]) plt.ylim([-0.05, 1.05]) plt.xlabel('False Positive Rate') plt.ylabel('True Positive Rate') plt.title('Receiver operating characteristic example') plt.legend(loc="lower right") plt.show()