擅长:python、mysql、java
<p><a href="https://github.com/scikit-learn/scikit-learn/blob/master/sklearn/metrics/classification.py" rel="noreferrer">https://github.com/scikit-learn/scikit-learn/blob/master/sklearn/metrics/classification.py</a></p>
<blockquote>
<p>F1 = 2 * (precision * recall) / (precision + recall)</p>
</blockquote>
<p>precision=TP/(TP+FP),正如你刚才说的,如果predictor根本不预测正类,那么precision是0。</p>
<p>回忆=TP/(TP+FN),如果预测因子不能预测阳性类别-TP为0-回忆为0。</p>
<p>现在你把0/0除以。</p>