title: Swapping Column values based on condition
body: <p>this is my dataframe</p>
  <pre><code>S.No    Column1 Column2
  0   7   A   B
  1   2   D   F
  2   5   C   H
  3   9   NaN J
  4   1   T   G
  5   4   Z   True
  6   10  S   Y
  7   3   G   V
  8   10  R   Y
  9   8   T   X
  
  df.replace([np.nan,True],'A',inplace=True)
  
      S.No    Column1 Column2
  0   7   A   B
  1   2   D   F
  2   5   C   H
  3   9   A   J
  4   1   T   G
  5   4   Z   A
  6   10  S   Y
  7   3   G   V
  8   10  R   Y
  9   8   T   X
  </code></pre>
  <p>required output be like</p>
  <pre><code>    S.No    Column1 Column2
  0   7   B   A
  1   2   F   D
  2   5   H   C
  3   9   J   A
  4   1   T   G
  5   4   Z   A
  6   10  Y   S
  7   3   V   G
  8   10  Y   V
  9   8   X   T
  </code></pre>
  <p>HOW TO WRITE CODE</p>