I want to design a grouped barplot for data arranged as follows
       sx1pre sx1post sx2pre sx2post   
1         1     1       1       0
2         1     0       1       0  
3         0     1       1       0 
4         1     0       0       1
5         1     0       1       0
6         1     0       1       0 
I want to compare for each sx (1 or 2) the frequency of"pre" and "post", in a single graph. I would like to graphically represent the percentages of patients showing one symptom (sx) before the operation (pre) , over the total, versus the the ones that show the same symptom after (post). Thanks
 
    
