python如何计算auc

Python (230) 2023-06-19 11:36:24


1、安装scikit-learn

1.1 Scikit-learn 依赖

·Python (>= 2.6 or >= 3.3),

·NumPy (>= 1.6.1),

·SciPy (>= 0.9).

分别查看上述三个依赖的版本:

python-V

结果:

Python2.7.3
python-c'importscipy;printscipy.version.version'

scipy版本结果:

0.9.0
python-c"importnumpy;printnumpy.version.version"

numpy结果:

1.10.2

1.2 Scikit-learn安装

如果你已经安装了NumPy、SciPy和python并且均满足1.1中所需的条件,那么可以直接运行sudo

pipinstall-Uscikit-learn

执行安装。

2、计算auc指标

importnumpyasnp
fromsklearn.metricsimportroc_auc_score
y_true=np.array([0,0,1,1])
y_scores=np.array([0.1,0.4,0.35,0.8])
roc_auc_score(y_true,y_scores)

输出:

0.75

3、计算roc曲线

importnumpyasnp
fromsklearnimportmetrics
y=np.array([1,1,2,2])#实际值
scores=np.array([0.1,0.4,0.35,0.8])#预测值
fpr,tpr,thresholds=metrics.roc_curve(y,scores,pos_label=2)#pos_label=2,表示值为2的实际值为正样本
printfpr
printtpr
printthresholds

输出:

array([0.,0.5,0.5,1.])
array([0.5,0.5,1.,1.])
array([0.8,0.4,0.35,0.1])

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