title: Replace spaces in a list
body: <p>I want to replace my_string </p>
  
  <pre><code>my_string = '[[4.6, 4.3, 4.3], [8.75, 5.6, 6.6], [4.6, 4.3, 4.3]]'
  </code></pre>
  
  <p>such that it gives result like this</p>
  
  <pre><code>my_string = '4.6x4.3x4.3 8.75x5.6x6.6 4.6x4.3x4.3'
  </code></pre>
  
  <p>I have tried this but this fills up the empty space with "x" too</p>
  
  <pre><code>mystring = mystring.replace("[","").replace("]","").replace(", ","x")
  </code></pre>
  
  <p>Is there a better pythonic way to do this ?</p>