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

mn <- pmin(s$to, s$from)
mx <- pmax(s$to, s$from)
int <- as.numeric(interaction(mn, mx))
s[match(unique(int), int),]
  section time to from
1       a    9  1    2
3       a   12  2    3
4       a   12  2    4
6       a   12  3    4

Credit for the idea goes to this question: Remove consecutive duplicates from dataframe and specifically @MatthewPlourde's answer.

Answer 2

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