title: How to sort a column from ascending order for EACH ID in R
body: <p>If I want to sort the Chrom# from ascending order (1 to 23) for each unique ID (as shown below there's multiple rows of same IDs, how to write the R code for it? eg) MB-0002, chrom from 1,1,1,2,4,22... etc. 1 chrom per row. I am new to R so any help would be appreciated. Thanks so much!</p>
  
  <p><a href="http://i.stack.imgur.com/Rms6M.png" rel="nofollow">sample dataset</a></p>