How to convert data to an edge list

I'm currently analysing survey data about people's preferred music genres. I want to build a network to show which genres people often enjoy in tandem.

I'm not sure what the best way to format my data is. It's currently in a form like this:

         Genre A Genre B Genre C 
Person A 1       1       1
Person B 1       1       0 
Person C 1       1       0 

Where a 1 indicates that they enjoy it, and a 0 that they don't. I'd like the network to connect genres and for the edges to show how often they're connected. I think the igraph package would work, but I need to convert my data to an edge list first.

Here's some quick code to set up the table in case you need it:

read.table(text = 
"GenreA GenreB GenreC 
PersonA 1 1 1
PersonB 1 1 0 
PersonC 1 1 0 
", header = TRUE)

I'm not really sure where to start.

If you convert your data frame to a matrix, then the cross-product of this matrix will be equivalent to the adjacency matrix of the desired graph.

library(igraph)

g <- as.matrix(df) |>
       crossprod() |>
       graph_from_adjacency_matrix(mode = 'undirected', diag = FALSE) 

Now g is your actual graph (network object)

plot(g)

And if you want it as an edgelist, you can do:

as_edgelist(g)
#>      [,1]     [,2]    
#> [1,] "GenreA" "GenreB"
#> [2,] "GenreA" "GenreB"
#> [3,] "GenreA" "GenreB"
#> [4,] "GenreA" "GenreC"
#> [5,] "GenreB" "GenreC"

^{Created on 2023-08-18 with reprex v2.0.2}