title: Left shift columns in R
body: <p>I have a data set like this</p>
  
  <pre><code>temp &lt;- structure(list(col_1 = c("", "P9603", "", "", "11040", 
  "80053"), col_2 = c("84484", "80061", "", "80061", "A0428", "85025"
  ), col_3 = c("V2632", "82310", "", "", "", "86357"), col_4 = c("J1170", 
  "84305", "62311", "80061", "", ""), col_5 = c("", "86708", "J0690", 
  "", "", "")), .Names = c("col_1", "col_2", "col_3", "col_4", 
  "col_5"), class = c("data.table", "data.frame"))
  
     col_1 col_2 col_3 col_4 col_5
  1:       84484 V2632 J1170      
  2: P9603 80061 82310 84305 86708
  3:                   62311 J0690
  4:       80061       80061                        
  5: 11040 A0428                  
  6: 80053 85025 86357 
  </code></pre>
  
  <p>Is there a possibility to shift the columns like this</p>
  
  <pre><code>   col_1 col_2 col_3 col_4 col_5
  1: 84484 V2632 J1170              #LEFT SHIFT 1
  2: P9603 80061 82310 84305 86708  #NO CHANGE
  3: 62311 J0690                    #LEFT SHIFT 3
  4: 80061 80061                    #LEFT SHIFT 1 FOR FIRST ITEM, 
                                    #LEFT SHIFT 2 FOR 2ND ITEM 
  5: 11040 A0428                    #NO CHANGE
  6: 80053 85025 86357              #NO CHANGE
  </code></pre>
  
  <p>I am shifting columns left, if the value on left is empty</p>