title: combining multiple columns in a single line with headers as variables
body: <p>Essentially my issue is thus I have 5 columns which must be combined into a 6th column that lines up all the data (x's in this case) what I would like to do is store the Header  as some kind of variable that can be read into something similar to .combine_first. the issue I'm having is that .combine first, as well as a few other series I've attempted to use only allow me to combine things one at a time instead of reading in all the column headers i want combined. the current solution is to combine each element separately and drop all the extra columns. Originally my issues was with getting the Nan to fill now I just need a quicker way to do what I'm doing.</p>
  
  <p>What I need</p>
  
  <pre><code>Var = Name1, Name2, Name3, Name4, Name5 
  
      something that combines all the elements
  
   My New Column
  
  </code></pre>
  
  <p>Current Solution (Works but too lengthy to be useable)</p>
  
  <pre><code>df['c'] = df['Name1'].combine_first(df['Name2'])
  df['c1'] = df['c'].combine_first(df['Name3'])
  df['c2'] = df['c1'].combine_first(df['Name4'])
  df['Names'] = df['c2'].combine_first(df['Name5'])
  df = df.drop(['Name1','Name2','Name3','Name4','Name5','c','c1','c2'], axis=1)
  </code></pre>
  
  <p>Issue</p>
  
  <pre><code>       Name1    Name2   Name3   Name4   Name5
  
            X      NaN     NaN    NaN      NaN
            X      NaN     NaN    NaN      NaN
            X      NaN     NaN    NaN      NaN
          NaN       X      NaN    NaN      NaN
          NaN       X      NaN    NaN      NaN
          NaN       X      NaN    NaN      NaN
          NaN      NaN      X     NaN      NaN
          NaN      NaN      X     NaN      NaN
          NaN .    NaN      X     NaN      NaN
          NaN      NaN     NaN    X        NaN
          NaN      NaN     NaN    X        NaN
          NaN      NaN     NaN    X        NaN
          NaN      NaN     NaN    NaN       X
          NaN      NaN     NaN    NaN       X
          NaN      NaN     NaN    NaN       X
  </code></pre>
  
  <p>Desired Result</p>
  
  <pre><code>Names
  0   X
  1   X
  2   X
  3   X
  4   X
  5   X
  6   X
  7   X
  8   X
  9   X
  10  X
  11  X
  12  X
  13  X
  14  X
  
  </code></pre>