title: Python Pandas replace values by their opposite sign
body: <p>I am trying to "clean" some data. I have values which are negative, which they cannot be. And I would like to replace all values that are negative to their corresponding positive values.</p>
  
  <pre><code>A    | B     | C
  -1.9 | -0.2  | 'Hello'
  1.2  | 0.3   | 'World'
  </code></pre>
  
  <p>I would like this to become</p>
  
  <pre><code>A    | B     | C
  1.9  | 0.2   | 'Hello'
  1.2  | 0.3   | 'World'
  </code></pre>
  
  <p>As of now I have just begun writing the replace statement</p>
  
  <pre><code>df.replace(df.loc[(df['A'] &lt; 0) &amp; (df['B'] &lt; 0)],df * -1,inplace=True)
  </code></pre>
  
  <p>Please help me in the right direction</p>