title: Python - make string equal length
body: <p>I have a RNA sequence of varying length. Max length of the sequence is 22. Some sequences are shorter. So if a sequence is shorter then add "0" to the end of the line till the length becomes 22.</p>
  
  <p>How to do it in python?
  this is my input </p>
  
  <p>AAGAUGUGGAAAAAUUGGAAUC</p>
  
  <p>CAGUGGUUUUAUGGUAG</p>
  
  <p>CUCUAGAGGGUUUCUG</p>
  
  <p>UUCAUUCGGC</p>
  
  <p>and my expected ouput should be for example in the last line it does not contain 22 characters so  i need to make it 22 by adding zero to it </p>
  
  <p>UUCAUUCGGC000000000000</p>
  
  <p>but as per your commands i am getting out put as 
  AAGAUGUGGAAAAAUU
  00000
  the addtional characters used for justification came down and not in the same line </p>