ID           date                 qid      aid     all
1  Sat Apr 11 2015 at 09:20:31    5522     777;    771;777;772
2  Sun Apr 24 2015 at 07:20:31    5522     777;    772;777;771

777 772
                                      777 777

df<-read.table("pp.txt", header=T,sep=",")

df$date<- strptime(df$date, format('%d/%b/%Y:%H:%M:%S'))