Remove duplicate column pairs, sort rows based on 2 columns [duplicate]

Answer 1

Instead of sorting for the whole dataset, sort the 'Var1', 'Var2', and then use duplicated to remove the duplicate rows

testdata[1:2] <- t( apply(testdata[1:2], 1, sort) )
testdata[!duplicated(testdata[1:2]),]
#   Var1 Var2       f       g
#1    1    4    blue    blue
#2    2    3   green   green
#5    5    5 orange2 orange1