擅长:python、mysql、java
<p>使用<a href="https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.count_nonzero.html" rel="noreferrer">^{<cd1>}</a>怎么样,比如</p>
<pre><code>>>> import numpy as np
>>> y = np.array([1, 2, 2, 2, 2, 0, 2, 3, 3, 3, 0, 0, 2, 2, 0])
>>> np.count_nonzero(y == 1)
1
>>> np.count_nonzero(y == 2)
7
>>> np.count_nonzero(y == 3)
3
</code></pre>