title: Python pandas preserving decimal commas in the output csv file
body: <p>I'm using pandas library to do some operations on <code>.csv</code> file.</p>
  
  <p>Input file <code>input.csv</code>:</p>
  
  <pre><code>    A    B   
     1,2  2,2
     3,5  5,4 
  </code></pre>
  
  <p>My code:</p>
  
  <pre><code>import pandas as pd
  
  df = read_csv('input.csv', sep = ';', encoding = 'ANSI', decimal = ',')
  '''
  some operations on cells like adding, multiplying...  
  '''
  
  df.to_csv('output.csv', sep = ';', encoding = 'ANSI', index = False)
  </code></pre>
  
  <p>And here is how my <code>output.csv</code> looks like:</p>
  
  <pre><code>    A    B    C   
     1.2  2.2  6.5
     3.5  5.4  7.8
  </code></pre>
  
  <p>But is there any way to keep my decimal separator as comma like there was in the <code>input.csv</code>?</p>
  
  <p>Here is how <code>output.csv</code> should look like:</p>
  
  <pre><code>    A    B    C   
     1,2  2,2  6,5
     3,5  5,4  7,8 
  </code></pre>
  
  <p>I have tried something like this but it didn't work:</p>
  
  <pre><code>df = df.astype(str).replace('.',',')
  </code></pre>