Compare group of two columns and return index matches R

Question

Many thanks for reading. Apologies for what I\'m sure is a simple task.

I have a dataframe: (Edited: Added extra column not to be included in comparison)

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Answer 1

You could do something like this. It splits the row indices 1:nrow(df) according to unique sorted strings formed from the columns of df. The sorting ensures that A,B and B,A are treated identically.

duplist <- split(1:nrow(df),apply(df,1,function(r) paste(sort(r),collapse=" ")))

duplist
$`alan edd`
[1] 2 6

$`alex david`
[1] 1

$`ben pete`
[1] 3 4

$`raymond richard`
[1] 5