title: How to split data in 2 different columns in a qplot() jitter chart?
body: <p>Hi there I have this set of data : </p>
  
  <pre><code> my.data=read.table(text="         values tag class
   1   100.0000000  X3    CS
   2   100.0000000  X5    CS
   3    54.2370601  X7    CS
   4    63.4813701  X7    CS
   5    51.0402580  X7    CS
   6    60.1430236  X7    CS
   7    70.3939619  X7    CS
   8    56.5981165  X7    CS
   9    75.4148038  X7    CS
   10   88.2687052  X7    CS
   11   70.9697583  X7    CS
   12   54.2014007  X7    CS
   13   63.4325244  X7    CS
   14   51.0086771  X7    CS
   15   60.1034812  X7    CS
   16   70.3397973  X7    CS
   17   56.5630966  X7    CS
   18   75.3652206  X7    CS
   19   88.2007869  X7    CS
   20   70.9258461  X7    CS
   21   38.6325912  X9    CS
   22   27.7455102  X9    CS
   23   21.1778773  X9    CS
   24  100.0000000  X9    CS
   25   73.0803007  X9    CS
   26   55.7814809  X9    CS
   27   85.8614803  X9    CS
   28   38.5666461  X9    CS
   29   27.7114796  X9    CS
   30   21.1580450  X9    CS
   31   72.9906659  X9    CS
   32   55.7292434  X9    CS
   33   85.7810739  X9    CS
   34    0.0000000 XAS    CS
   35   49.0701633 XPW    CS
   36   40.0228822 XPW    CS
   37   23.8702273 XPW    CS
   38  100.0000000 XPW    CS
   39   89.3022370 XPW    CS
   40   53.2611491 XPW    CS
   41   69.9892886 XPW    CS
   42    0.0000000 XPW    CS
   43   14.8840750  X3    CD
   44   17.7316138  X3    CD
   45    6.1164435  X3    CD
   46    0.0000000  X3    CD
   47    1.1435141  X3    CD
   48   14.8904265  X3    CD
   49   17.7375474  X3    CD
   50    6.1241709  X3    CD
   51    1.1506441  X3    CD
   52   14.6751282  X3    CD
   53   17.5364297  X3    CD
   54    5.8621689  X3    CD
   55    0.9089743  X3    CD
   56   74.4165986  X5    CD
   57   76.7441666  X5    CD
   58   80.9582780  X5    CD
   59   58.5811936  X5    CD
   60   62.3494607  X5    CD
   61   69.1719883  X5    CD
   62   57.2509995  X5    CD
   63   61.1402872  X5    CD
   64   68.1819250  X5    CD
   65   74.3887236  X5    CD
   66   76.7211353  X5    CD
   67   80.9428400  X5    CD
   68   58.5360647  X5    CD
   69   62.3121736  X5    CD
   70   69.1469947  X5    CD
   71   57.2044213  X5    CD
   72   61.1018026  X5    CD
   73   68.1561287  X5    CD
   74   74.3425809  X5    CD
   75   76.6830205  X5    CD
   76   80.9173038  X5    CD
   77   58.4613610  X5    CD
   78   62.2504669  X5    CD
   79   69.1056522  X5    CD
   80   57.1273184  X5    CD
   81   61.0381141  X5    CD
   82   68.1134585  X5    CD
   83   66.3076784  X7    CD
   84   60.5650688  X7    CD
   85   68.2935472  X7    CD
   86   49.3767792  X7    CD
   87   40.7484217  X7    CD
   88   52.3605769  X7    CD
   89   36.4202616  X7    CD
   90   25.5835605  X7    CD
   91   40.1677332  X7    CD
   92   66.3298303  X7    CD
   93   60.5954120  X7    CD
   94   68.3131654  X7    CD
   95   49.4100626  X7    CD
   96   40.7940127  X7    CD
   97   52.3900536  X7    CD
   98   36.4620636  X7    CD
   99   25.6408202  X7    CD
   100  40.2047541  X7    CD
   101  66.1477122  X9    CD
   102  75.6876522  X9    CD
   103  81.4426220  X9    CD
   104  55.0173821  X9    CD
   105  67.6939692  X9    CD
   106  75.3411217  X9    CD
   107  51.6125069  X9    CD
   108  65.2486246  X9    CD
   109  73.4746140  X9    CD
   110  66.2054974  X9    CD
   111  75.7174719  X9    CD
   112  81.4600003  X9    CD
   113  55.0941665  X9    CD
   114  67.7335933  X9    CD
   115  75.3642139  X9    CD
   116  51.6951034  X9    CD
   117  65.2912480  X9    CD
   118  73.4994541  X9    CD
   119  25.6270138 XAS    CD
   120  45.2920118 XAS    CD
   121  44.5101287 XAS    CD
   122   0.0000000 XAS    CD
   123  17.9916840 XAS    CD
   124  16.8196263 XAS    CD
   125   7.3447585 XPW    CD
   126  24.4280115 XPW    CD
   127  54.9277702 XPW    CD
   128   0.0000000 XPW    CD
   129   4.6378241 XPW    CD
   130  43.1246155 XPW    CD
   131  39.7525599 XPW    CD
   132 100.0000000 XPW    CD")
  </code></pre>
  
  <p>Plotting those data with qplot() gives me the following result : </p>
  
  <pre><code>qplot(tag,values,colour=factor(class),data=my.data,geom="jitter")+stat_summary(fun.y='mean', geom='errorbarh', aes(xmin=as.integer(tag)-0.3, xmax=as.integer(tag)+0.3), height=0)
  </code></pre>
  
  <p><img src="https://s24.postimg.org/kv1917fg5/Rplot.jpg" alt="jitter plot"></p>
  
  <p>I would like to split blue and red points from the same columns into 2 separate and right by each other columns to give something like this but with my jitter points :</p>
  
  <p><img src="https://blogs.sas.com/content/sascom/files/2011/08/ClusterGroupBar_SAS92M3.png" alt="example"></p>
  
  <p>And since we're at it do you know how to reduce the width of columns (reduce width space given to points from a given x) to make the columns narrower ? Also how to add space between columns or even an horizontal bar so we see clearly the different columns ?</p>