title: Python fill a list with the same string
body: <p>I have a pandas DataFrame and I would like to make a new column with the same string in each row. </p>
  
  <p>Currently I'm doing this. </p>
  
  <pre><code>tag=[]
  for x in xrange(len(preds)): #preds is a np.array, same length of df
      tag.append('MY STRING')
   df['TAG']=tag
  </code></pre>
  
  <p>I know there must be a smarter way to do this. </p>
  
  <p>Any help is appreciated. </p>