title: Why df have '.0' when I to txt?
body: <pre><code>t=pd.DataFrame(tree_pre)
  
  t.fillna('',inplace=True)
  
  print(t)
  
      0   1   2   3   4   5   6   7 8
  0          55                      
  1      30                  70      
  2  25                  65      85  
  3              60                  
  4                  64  
  
  </code></pre>
  
  <p>but when I to txt</p>
  
  <pre><code>t.to_csv('2020.txt',sep='\t',index=False,header=False)
  </code></pre>
  
  <p>The txt have '.0'</p>
  
  <pre><code>    55.0                        
  30.0                    70.0        
  </code></pre>
  
  <p>25.0                    65.0        85.0<br>
              60.0<br>
                  64.0                </p>
  
  <p>Why df have '.0' when I to txt?</p>