Error when trying to load dl format using igraph - r

Question

I am trying to load the kapferer min dataset into r using the igraph function "read_graph"
The code is very simple, however it throws an error.
test_g <-read_graph("http://vlado.fmf.uni-lj.si/pub/networks/data/ucinet/kapmine.dat", format = "dl")
Error in read.graph.dl(file, ...) : At foreign.c:3050 : syntax
error, unexpected $end, expecting DL in line 1, Parse error
The as can be seen by following the link the file does begin with DL. The only clue I can find to this is a message from 2015 which basically says file a bug report.
Can dl files not beloaded by igraph at the moment, or is there some trick to it?

Answer 1

As there doesn't seem to be a clear way to load dl files I have made a loader that seems to work well for dl graph on the Pajek website. The function is a bit scrappy and has not been extensively tested, but it may be useful to some who want to use certain graphs that are not available in a more common format. If there is more to date information on these datasets, then this code can be ignored.
load_dl_graph <- function(file_path, directed){
raw_mat <- readLines(file_path) %>%
enframe()
row_labels_row <- grep( "ROW LABELS:", raw_mat$value)
column_labels_row <- grep( "COLUMN LABELS:", raw_mat$value)
level_labels_row <- grep("LEVEL LABELS:",raw_mat$value )
data_table_row <- grep( "DATA:", raw_mat$value)
row_labels <- raw_mat %>%
slice((row_labels_row+1):(column_labels_row-1)) %>%
select(from = value)
column_labels <- raw_mat %>%
slice((column_labels_row+1):(level_labels_row-1)) %>% pull(value)
table_levels <- raw_mat %>%
slice((level_labels_row+1):(data_table_row+-1)) %>% pull(value)
data_df <- raw_mat %>%
slice((data_table_row+1):nrow(.)) %>%
select(value) %>%
mutate(value = str_squish(value)) %>%
separate(col = value, into = column_labels, sep = " ") %>%
mutate(table_id = rep(1:length(table_levels), each = nrow(.)/length(table_levels)))
tables_list <- 1:length(table_levels) %>%
map(~{
data_df %>%
filter(table_id ==.x) %>%
select(-table_id) %>%
bind_cols(row_labels,.) %>%
pivot_longer(cols = 2:ncol(.), names_to = "to", values_to = "values") %>%
filter(values ==1) %>%
select(-values) %>%
graph_from_data_frame(., directed = directed)
})
names(tables_list) <- table_levels
return(tables_list)
}