擅长:python、mysql、java
<p>您需要将数组的索引从<code>m</code>更改为<code>i</code>,才能真正更改值。
结果:</p>
<pre class="lang-py prettyprint-override"><code>import numpy as np
n = 20
m = 5
#generate an array a
a = np.random.randint(0,2,n)*2-1
print(a)
#random choose `i` element and flip it.
for i in np.random.randint(0,n,m):
a[i] = -a[i]
print(a)
</code></pre>
<p>我的输出:</p>
^{pr2}$