R igraph - Convert a weighted adjacency matrix into weighted edgelist
igraph, matrix, r
Solution
library(igraph)
set.seed(1) # for reproducible example
myAdjacencyMatrix <- matrix(runif(400),nc=20,nr=20)
g <- graph.adjacency(myAdjacencyMatrix,weighted=TRUE)
df <- get.data.frame(g)
head(df)
# from to weight
# 1 1 1 0.2655087
# 2 1 2 0.9347052
# 3 1 3 0.8209463
# 4 1 4 0.9128759
# 5 1 5 0.4346595
# 6 1 6 0.6547239
You need to use `weighted=TRUE` in the call to `graph.adjacency(...)` to have weights assigned to the edges. Then, `get.data.frame(...)` will return a data frame of the edges with all edge attributes by default. You can use the `what=...` argument to return, e.g., the vertex list with attributes.
In future: provide an example, rather than forcing us to create one for you!!!
Problem
I have a nxm adjacency matrix, where (i,j) represent the score of association between i and j. I need to convert this into the following format like : `i j <score1>` using R' igraph package and output it into a text file. I can derive the edgelist, but its showing up without the weights. I used the following code: `library(igraph) g <- graph.adjacency(myAdjacencymatrix) get.edgelist(g)` However, it does not show the weights.