擅长:python、mysql、java
<p>完成这类任务有很多方法。这里有一个简单的方法。你知道吗</p>
<pre><code># Get the array length
N = len(my_array)
# Proportion of 1's
p = np.sum(my_array) / float(N)
# Locations of 1's
idx = np.arange(0, N)[my_array == 1]
# Calculate how many idx to change
k = (p*N) - (0.2 * N)
# Sample the idx and change values to 0
my_array[np.random.choice(idx, int(k), False)] = 0
</code></pre>