title: How to add last row as Total in dataframe in R
body: <p>I have below-mentioned column in R:</p>
  
  <pre><code>structure(list(product = c("-", "A", "B", "CC", "XA", "RD", 
  "IS", "FD"), count.1 = c(969, 324, 11, 161, 185, 79, 231, 9), 
      Per.1 = c(49.21, 16.46, 0.56, 8.18, 9.4, 4.01, 11.73, 
      0.46), remark = c("F2", "", "F1", "NA", "K4", "-", 
      "-", "-"), count.2 = c("1708", "215", "35", "9", "2", "-", 
      "-", "-"), per.2 = c(86.74, 10.92, 1.78, 0.46, 0.1, 
      NA, NA, NA), status = c("Go", "hold", "-", "-", "-", "-", "-", 
      "-"), count.3 = c("1717", "200", "52", "-", "-", "-", "-", 
      "-"), per.3 = c(87.2, 10.16, 2.64, NA, NA, NA, NA, 
      NA)), .Names = c("product", "count.1", "per.1", "remark", 
  "count.2", "per.2", "status", "count.3", "per.3"
  ), row.names = c(NA, -8L), class = c("data.table", "data.frame"
  ), .internal.selfref = &lt;pointer: 0x185b2f8&gt;)
  </code></pre>
  
  <p>I want to sum from column 2 to 9 and add <code>%</code> sign in column 3,6 and 9.</p>
  
  <p>Request Output like:</p>
  
  <pre><code>product   count.1 per.1   remark   count.1  per.2     Status  count.3  per.3           
  -         969     49.21%   F2      1708     86.74%      Go    1717     87.20%
  A         324     16.46%           215      10.92%      Hold  200      10.16%
  B         11      0.56%    F1      35       1.78%       -     52       2.64%
  CC        161     8.18%    NA      9        0.46%       -     -        NA
  XA        185     9.40%    K4      2        0.10%       -     -        NA
  RD        79      4.01%     -      -        NA          -     -        NA
  IS        231     11.73%    -      -        NA          -     -        NA
  RD        9       0.46%     -      -        NA          -     -        NA
  Total     1969    100.01%   -      1969    100.00%      -     1969     100.00%  
  </code></pre>