title: R-how to add dynamically column in dataframe based on list of variable increses
body: <p>I need to achieve below task; can you please help me to do it.</p>
  
  <p>My dataframe.</p>
  
  <pre><code>U_ID  Value                                          AD   CT
      1     list(`Cno`="50",`cna'="jhon")               ia   BG
      1     list(`Cno`="20",`cna'="guna")               AS   DB
      2     list(`Cno`="30",`cna'="rt",`cf'="ty")       BN   FV
      2     NULL                                        VF   TY
      3     list(`Cno`="30")                            RR   TT
  </code></pre>
  
  <p>My desired output will be  </p>
  
  <pre><code>U_ID  Value                                 Cno   cna   cf      AD   CT
  1     list(`Cno`="50",`cna'="jhon")         50    jhon  NULL    ia   BG
  1     list(`Cno`="20",`cna'="guna")         20   guna  NULL    AS   DB
  2     list(`Cno`="30",`cna'="rt",`cf'="ty") 30   rt    ty      BN   FV
  2     NULL                                 NULL  NULL  NULL    VF   TY
  3     list(`Cno`="30")                     30    NULL  NULL     RR   TT
  </code></pre>
  
  <p>Data:</p>
  
  <pre><code>structure(list(U_ID = c(1, 1, 2, 2, 3), Value = list(structure(list(
      `Cno#` = "50", cna = "jhon"), .Names = c("Cno#", "cna")), 
      structure(list(`Cno#` = "50", cna = "guna"), .Names = c("Cno#", 
      "cna")), structure(list(`Cno#` = "30", cna = "rt", cf = "ty"), .Names = c("Cno#", 
      "cna", "cf")), "NULL", structure(list(`Cno#` = "30"), .Names = "Cno#")), 
      AD = c("ia", "AS", "BN", "VF", "RR"), CT = c("BG", "DB", 
      "FV", "TY", "TT")), .Names = c("U_ID", "Value", "AD", "CT"
  ), row.names = c(NA, -5L), class = "data.frame")
  </code></pre>