title: Pandas: adding one space around value in string column
body: <p>I swear this should be easy, but I can't find the answer.</p>
  <p>Example dataframe:</p>
  <pre><code>df = pd.DataFrame([['1', '3-3/4'], 
                     ['2', '1-1/2'],
                     ['3', '2'],
                     ['4', '5-1/4'],
                     ['5', '6']],
                    columns = [&quot;ID&quot;, &quot;Size&quot;])
  </code></pre>
  <p><a href="https://i.stack.imgur.com/5k0EM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5k0EM.png" alt="Example dataframe" /></a></p>
  <p>All I want to do is to add one space before and after the value in the Size column. I've tried ljust, rjust, center, and pad, but they all fail to add because you have to account for the length of the string, which varies.</p>
  <p>I want it to look something like this (pretend the x is a space):</p>
  <p><a href="https://i.stack.imgur.com/8l4ef.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8l4ef.png" alt="Needed outcome" /></a></p>
  <p>I've dug around online, but cannot find a way to resolve this. Would someone point me in the right direction?</p>
  <p>Thanks!</p>