title: Split one column into several columns on basis of a separator in R
body: <p>I have a question similar to the one found <a href="https://stackoverflow.com/questions/14760730/splitting-one-column-into-multiple-columns">here</a></p>
  
  <p>If I have a data structure like the following:</p>
  
  <pre><code> ROW_NO.        INPUT          STRAND
         1  1,888639,T,C             -1
         2  1,889158,G,C             NA                               
         3  1,889159,A,C             NA                                     
         4 1,978978,GC,G              1                                      
         5  1,982941,T,C             NA                                      
         6 1,1888193,C,A             -1
  </code></pre>
  
  <p>What do I need to do in order to split the INPUT column like so:</p>
  
  <pre><code> ROW_NO.        INPUT    Chrom     Position    Ref.y   Variant.y   
         1  1,888639,T,C    chr1       888639        T           C
         2  1,889158,G,C    chr1       889158        G           C                            
         3  1,889159,A,C    chr1       889159        A           C                                         
         4 1,978978,GC,G    chr1       978978       GC           G        
         5  1,982941,T,C    chr1       982941        T           C        
         6 1,1888193,C,A    chr1      1888193        C           A
  </code></pre>
  
  <p>And I'd keep the STRAND column where it was, though somehow while formatting everything got messed up here so I left it out.</p>