擅长:python、mysql、java
<p>答案在问题中</p>
<pre><code>'4' is not recognized as an internal or external command, operable program or batch file.
</code></pre>
<p>打开cmd并键入它将给出错误的任何内容,除非我们键入cmd可以识别的内容。e、 g一个帮助命令</p>
<p>如果我们想在cmd中输入一些东西,并让它在控制台上得到处理/打印,我们就使用一个命令</p>
<blockquote>
<p>echo</p>
</blockquote>
<p><a href="https://i.stack.imgur.com/WCR85.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WCR85.png" alt="enter image description here"/></a></p>
<p>在您的程序中,只有echo命令丢失,这将使您的输出打印在cmd上</p>
<p><a href="https://i.stack.imgur.com/Wcxhj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Wcxhj.png" alt="enter image description here"/></a></p>
<blockquote>
<p>Last but not the least, always remember the ZEN of Python</p>
</blockquote>
<p><a href="https://i.stack.imgur.com/8YN2u.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8YN2u.png" alt="enter image description here"/></a></p>