title: how to get this string using python
body: <p>i have a list like this :</p>
  
  <pre><code>a=[1000,200,30]
  </code></pre>
  
  <p>and i want to get a list like this :</p>
  
  <pre><code>['01000','00200','00030']
  </code></pre>
  
  <p>so what can i do ,</p>
  
  <p>thanks</p>