Remove duplicated 2 columns permutations

Question

I can\'t find a good title for this question so feel free to edit it please.

I have this data.frame

  section time to from
1       a    9  1    2
2           


        

Answer 1

You can try using sort within the apply function to order the combinations.

mydf[!duplicated(t(apply(mydf[3:4], 1, sort))), ]
#   section time to from
# 1       a    9  1    2
# 3       a   12  2    3
# 4       a   12  2    4
# 6       a   12  3    4