title: Is it possible to remove repeated columns/rows when plotting correlation matrix as heatmap in Seaborn?
body: <p>Given the next dataframe</p>
  
  <pre><code>my_df.head()
  
  
  
  cruce1  cruce2  cruce3  cruce4  cruce5  cruce6  cruce7  cruce8  cruce9  cruce10 ... factor75    factor80    factor85    factor90    factor95    factor100   factor105   factor110   factor115   factor120
  Date                                                                                    
  1993-10-28  0.0049  NaN NaN NaN NaN NaN NaN NaN NaN NaN ... 161.75  172.45  196.86  200.33  219.21  222.67  243.23  235.77  249.48  231.56
  1993-10-29  0.0002  0.0051  NaN NaN NaN NaN NaN NaN NaN NaN ... 169.13  172.64  211.90  205.58  218.63  223.16  250.21  245.71  256.47  245.63
  1993-11-01  0.0041  0.0043  0.0092  NaN NaN NaN NaN NaN NaN NaN ... 165.37  170.35  215.84  198.81  216.43  222.32  246.18  247.09  253.57  254.07
  1993-11-02  -0.0019 0.0022  0.0024  0.0073  NaN NaN NaN NaN NaN NaN ... 175.01  180.37  219.77  210.89  210.06  236.31  249.19  260.01  252.05  259.16
  1993-11-03  0.0023  0.0004  0.0045  0.0047  0.0096  NaN NaN NaN NaN NaN ... 183.84  177.68  210.58  207.35  207.67  228.06  235.10  254.71  251.55  258.43
  </code></pre>
  
  <p>With this columns:</p>
  
  <pre><code>my_df.head()
  
  Index(['cruce1', 'cruce2', 'cruce3', 'cruce4', 'cruce5', 'cruce6', 'cruce7',
         'cruce8', 'cruce9', 'cruce10', 'cruce11', 'cruce12', 'cruce13',
         'cruce14', 'cruce15', 'cruce16', 'cruce17', 'cruce18', 'cruce19',
         'cruce20', 'factor1', 'factor5', 'factor10', 'factor15', 'factor20',
         'factor25', 'factor30', 'factor35', 'factor40', 'factor45', 'factor50',
         'factor55', 'factor60', 'factor65', 'factor70', 'factor75', 'factor80',
         'factor85', 'factor90', 'factor95', 'factor100', 'factor105',
         'factor110', 'factor115', 'factor120'],
        dtype='object')
  </code></pre>
  
  <p>I make a heatmap plot of the correlation matrix</p>
  
  <pre><code>corr = my_df.diff().corr()
  
  mask = np.zeros_like(corr)
  mask[np.triu_indices_from(mask)] = True
  
  sns.heatmap(corr, mask=mask, linewidths=0.1, vmax=1.0, 
                      square=False, cmap=colormap, linecolor='white')
  </code></pre>
  
  <p>with the next result:</p>
  
  <p>Heatmap 1:</p>
  
  <p><img src="https://i.stack.imgur.com/phzrD.png" alt="Screenshot Heatmap 1"></p>
  
  <p>But I want to keep only the different columns in the heatmap:</p>
  
  <p>Heatmap 2:</p>
  
  <p><img src="https://i.stack.imgur.com/QPjyr.png" alt="Screenshot Heatmap 2"></p>
  
  <p>Is it possible to do it? And, if it is, can it be done by making the resulting square fill the blank space?</p>