Function to create network data objects

confNet.R

# There's probably a much neater way to do this but if it works, it works. And this? It works. 

set.seed(24)
df <- data.frame(col1 = rep(LETTERS[1:4], 10),
                col2 = rep(1:10, 4))

# Function to create network data objects ####
# - a data frame of usernames that interact with >1 hashtag ('dataframe')
# - edges and nodes used in creating networks ('edges', 'nodes')
# - the network object ('routes')
# from a list of data frames
# 
#
# See stepwise code, below, for a walk-through
# 
# l = list of data frames
#
confNet <- function(l){
  veCombine <- function(x,m){
    n <- ifelse(length(x) == 1,ifelse(is.numeric(x),x,1),length(x))
    if(n >= m) return(combn(x,m))
    a <- do.call(expand.grid, rep(list(x),m))
    b <- t(unique(t(apply(a,1,sort))))
    `dimnames<-`(b,NULL)
  }
  
  reCombine <-function(x, m){
    a <- veCombine(x, m)
    b <- data.frame(from = a[1,], to = a[2,])
    return(b)
  }
  
  list <- split(l, l$username)
  list <- list[sapply(list, function(x) dim(x)[1]) > 1]
  d <- lapply(list, function(x) reCombine(x$hashtag, 2))
  d2 <- plyr::ldply(d, data.frame)

  edges <- d2[!(d2$from == d2$to),]
  edges[,1] <- NULL
  edges<- na.omit(edges)
  names(edges) <- c("source", "destination")
  
  edges <- edges %>% 
    group_by(source, destination) %>% 
    summarise(n = n()) %>%
    mutate(n = scales::rescale(n, to = c(0:1))) %>%
    rename(weight = n) %>%
    ungroup()
  
  nodes <- data.frame(label = unique(d2$from), id = 1:length(unique(d2$from)))
  
  edges <- edges %>% 
    left_join(nodes, by = c("source" = "label"))  %>%
    rename(from = id)
  
  edges <- edges %>% 
    left_join(nodes, by = c("destination" = "label")) %>%
    rename(to = id)
  
  edges <- select(edges, from, to, weight)
  
  routes <- tbl_graph(nodes = nodes, edges = edges, directed = TRUE)
  
  routes %>% 
    activate(edges) %>% 
    arrange(desc(weight))
  
  o <- list(d2, edges, nodes, routes)
  names(o) <- c("dataframe", "edges", "nodes", "routes") 
  return(o)
}

netlist <- confNet(df)