title: Error in writing dataframe in csv
body: <p>i have below dataframe </p>
  
  <pre><code>df_Place:
      Name|Places
      ----+-----------------------
      abc |delhi
      bcd |mumbai,delhi
      cde |chennai,hyderabad,delhi
      def |mumbai
      efg |bangalore,mumbai
      ghi |delhi,bangalore
  </code></pre>
  
  <p>i wanted to have places in form of a matrix so i did below operation</p>
  
  <pre><code>df_Place$matrix&lt;-as.matrix(strsplit(df_Place$Place,","))
  </code></pre>
  
  <p>i get below dataframe</p>
  
  <pre><code>Name|Places                 |matrix
  ----+-----------------------+------------------------------
  abc |delhi                  |delhi
  bcd |mumbai,delhi           |c("mumbai","delhi")
  cde |chennai,hyderabad,delhi|c("chennai","hyderabad","delhi")
  def |mumbai                 |mumbai
  efg |bangalore,mumbai       |c("bangalore","mumbai")
  ghi |delhi,bangalore        |c("delhi","bangalore")
  </code></pre>
  
  <p>now while trying to write this into csv 
  write.csv(df_Place,"tx.csv")
  i get below error: 
  <strong>Error in .External2(C_writetable, x, file, nrow(x), p, rnames, sep, eol,  : 
    unimplemented type 'list' in 'EncodeElement'</strong></p>
  
  <p>but if i remove the matrix column then it gets written successfully. </p>
  
  <p>i know that it will be very basic, but can someone explain the reason behind this</p>