title: How do I change all negative numbers to zero in python?
body: <p>I have one list</p>
  
  <pre><code>    list1 = [-10,1,2,3,9,-1]
  </code></pre>
  
  <p>I want to change the negative number to zero so that it looks like </p>
  
  <pre><code>    list1 = [0,1,2,3,9,0]
  </code></pre>
  
  <p>how can I do it? Thanks!</p>