擅长:python、mysql、java
<p>您可以使用<code>enumerate()</code>:</p>
<pre><code>d = [-1,-2,-1,1,2,4,1,-1,-2,-4,-1,3,4,5,2,-2,-3,-1,3,4,3,1,-1,-3,-2,-1,2,3,4]
count = 0
for i,n in enumerate(d):
if i < len(d)-1 and d[i] > 0 and d[i+1] < 0:
count += 1
print(count)
</code></pre>
<p>输出:</p>
<pre><code>3
</code></pre>
<p><a href="https://i.stack.imgur.com/gOwJy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gOwJy.png" alt="enter image description here"/></a></p>