擅长:python、mysql、java
<p>改变</p>
<pre class="lang-py prettyprint-override"><code>print("This is how much money you will have after {} years: ").format(years) + str(final_amount)
</code></pre>
<p>到</p>
<pre class="lang-py prettyprint-override"><code>print("This is how much money you will have after {} years: ".format(years)) + str(final_amount)
</code></pre>
<p><code>format()</code>是<code>string</code>类的一个方法。您正在<code>print()</code>函数上使用它,它是<code>NoneType</code>的函数,因此出现了错误</p>