Remove duplicates column combinations from a dataframe in R

Question

I want to remove duplicate combinations of sessionid, qf and qn from the following data

               sessionid             qf        qn         city
1  9         


        

Answer 1

To address your sorting problems, first reading in your example data:

dat <- read.table(text = "               sessionid             qf        qn         city
1  9cf571c8faa67cad2aa9ff41f3a26e38     cat   biddix          fresno
2  e30f853d4e54604fd62858badb68113a   caleb     amos             NA   
3  2ad41134cc285bcc06892fd68a471cd7  daniel  folkers             NA   
4  2ad41134cc285bcc06892fd68a471cd7  daniel  folkers             NA   
5  63a5e839510a647c1ff3b8aed684c2a5 charles   pierce           flint
6  691df47f2df12f14f000f9a17d1cc40e       j    franz prescott+valley
7  691df47f2df12f14f000f9a17d1cc40e       j    franz prescott+valley
8  b3a1476aa37ae4b799495256324a8d3d  carrie mascorro            brea
9  bd9f1404b313415e7e7b8769376d2705    fred  morales       las+vegas
10 b50a610292803dc302f24ae507ea853a  aurora      lee              NA  
11 fb74940e6feb0dc61a1b4d09fcbbcb37  andrew    price       yorkville ",sep = "",header = TRUE)

and then you can use arrange from plyr,

arrange(dat,sessionid,qf,qn)

or using base functions,

with(dat,dat[order(sessionid,qf,qn),])