title: Change name in every iteration in Python in order to save
body: <p>I was wondering how can i change the name of a file inside a for loop in order to save it with different consecutive names. e.g</p>
  
  <pre><code>for i in range(0, np.max(idx)+1):    
      vars()['cluster' + str(i)]= [tracks[x] for x in range(len(tracks)) if idx[x] == i]
      function_to_write("/Users/George/Desktop/file.bmp", vars()['cluster' + str(i)])  
  </code></pre>
  
  <p>How can i change the FileName in order to be file1, file2 etc ?  </p>