title: Combing dataframe values to a new dataframe
body: <p>I am combining two dataframe values from an Excel file to a new dataframe but the combined values changed to decimal number. Here are my codes:</p>
  
  <p>My dataframe that I wish to combine:</p>
  
  <pre><code>cable_block    pair
  1              10
  1              11
  3              123
  3              222
  </code></pre>
  
  <p>I insert a dataframe to have those two combined with a delimiter of <code>/</code>, so here is my code:</p>
  
  <pre><code>df['new_col'] = df[['cable_block', 'pair']].apply(lambda x: '/'.join(x.astype(str), axis=1))
  </code></pre>
  
  <p>The result I get is:</p>
  
  <pre><code>cable_block    pair   new_col
  1              10     1.0/10.0
  1              11     1.0/11.0
  3              123    3.0/123.0
  3              222    3.0/222.0
  </code></pre>
  
  <p>After searching, I found good answer by 
  <a href="https://stackoverflow.com/questions/42676982/python-turn-all-items-in-a-dataframe-to-strings">here</a> Psidom and Skirrebattie. So I tried:</p>
  
  <pre><code>df['new_col'] = df['new_col'].applymap(str)
  </code></pre>
  
  <p>and</p>
  
  <pre><code>df['new_col'] = df['new_col'].astype(str)
  </code></pre>
  
  <p>But it doesn't work the way it should. Looking by the codes, it should work and I find it weird that it doesn't. </p>
  
  <p>Is there another work around?</p>