擅长:python、mysql、java
<p>这是<code>np.select()</code>函数的一个很好的例子<a href="https://numpy.org/doc/stable/reference/generated/numpy.select.html" rel="nofollow noreferrer">The docs can be found here</a></p>
<p>设置很简单:</p>
<ul>
<li>创建<code>list</code>丹麦系统等级</李>
<li>创建<code>list</code>个映射。下面的案例使用逻辑and<code>&</code>运算符链接多个条件</李>
</ul>
<p>设置:</p>
<pre><code>import numpy as np
# Sample grades.
x = np.array([-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12])
# Define limits and lookup.
grades = [12, 10, 7, 4, 2, 0, -3]
scale = [(x >= 11),
(x >= 8.5) & (x < 11),
(x >= 5.5) & (x < 8.5),
(x >= 3.0) & (x < 5.5),
(x >= 1.0) & (x < 3.0),
(x >= -1.5) & (x < 1.0 ),
(x < -1.5)]
</code></pre>
<p>用法:<br/>
调用<code>np.select</code>函数并传入上面创建的两个列表</p>
<pre><code># Map grades to Danish system.
np.select(condlist=scale, choicelist=grades)
</code></pre>
<p>输出:</p>
<pre><code>array([-3, -3, 0, 0, 2, 2, 4, 4, 4, 7, 7, 7, 10, 10, 12, 12])
</code></pre>