r - 合并 Igraph 时保持属性名称

Question

问题

我有两个没有重叠节点或边缘的独立网络，它们都具有相同的属性。我想将这两个网络组合成一个网络，然后由两个不同的组件组成。

但是，当我尝试使用 union 合并它们时命令属性从“attribute”重命名为“attribute_1”和“attribute_2”。命令帮助文件中说明了这将发生，但我找不到合并这两个网络的明显方法。

情况如下面的代码块所示

library(igraph)

#create a 4 node network of two components
adjmat <- rep(0, 16)
adjmat[c(2,5,12,15)] <- 1
g <-  graph.adjacency(matrix(adjmat, nrow = 4) , mode = "undirected") 

#give attributes naming the nodes and the edges
g <- set_vertex_attr(g, "name", value = paste0("Node_", 1:4))
g <- set_edge_attr(g, "name", value = paste0("Edge_",1:2))

#I am interested in the type attribute
g <- set_edge_attr(g, "type", value = c("foo", "bar"))

plot(g)

#Decompose into seperate networks
gList <- decompose(g)

g2 <-union(gList[[1]], gList[[2]])

#vertices are fine but edges have been renamed as stated in the helpfile for union.
get.edge.attribute(g2)
get.vertex.attribute(g2)

解决方法

目前，这两个独立的网络源自同一个原始网络，所以我已经能够进行破解，但情况并非总是如此，我想要一种更多的 igraph 方式来合并两者。

黑客在下面

#To solve this problem I do the following

#Create two dataframes from the edge characteristics of the network and combine into a single dataframe
P <- rbind(as_data_frame(gList[[1]]),
               as_data_frame(gList[[2]]))

g3 <- set.edge.attribute(g, "type", value = P$type[match(P$name,  get.edge.attribute(g, "name"))]) 

#Edges are now correct
get.edge.attribute(g3)matrix(adjmat, nrow = 4) 
get.vertex.attribute(g3)

igraph 中是否有一个函数可以将两个单独的网络合并为一个网络，同时保持属性不变？

Answer 1

我制作了以下版本的联合，它接受两个具有任意数量重叠属性的图，并将它们合并到一个属性没有“_x”后缀的单个图中。这些图可以是完全独立的，也可以有重叠的节点。
在重叠节点的情况下，图 1 的属性优先

library(dplyr)
library(igraph)

union2<-function(g1, g2){

 #Internal function that cleans the names of a given attribute
 CleanNames <- function(g, target){
  #get target names
  gNames <- parse(text = (paste0(target,"_attr_names(g)"))) %>% eval 
  #find names that have a "_1" or "_2" at the end
  AttrNeedsCleaning <- grepl("(_\\d)$", gNames )
  #remove the _x ending
  StemName <- gsub("(_\\d)$", "", gNames)

  NewnNames <- unique(StemName[AttrNeedsCleaning])
  #replace attribute name for all attributes
  for( i in NewnNames){

   attr1 <- parse(text = (paste0(target,"_attr(g,'", paste0(i, "_1"),"')"))) %>% eval
   attr2 <- parse(text = (paste0(target,"_attr(g,'", paste0(i, "_2"),"')"))) %>% eval

   g <- parse(text = (paste0("set_",target,"_attr(g, i, value = ifelse(is.na(attr1), attr2, attr1))"))) %>%
             eval

   g <- parse(text = (paste0("delete_",target,"_attr(g,'", paste0(i, "_1"),"')"))) %>% eval
   g <- parse(text = (paste0("delete_",target,"_attr(g,'", paste0(i, "_2"),"')"))) %>% eval

   }

  return(g)
 }


 g <- igraph::union(g1, g2) 
 #loop through each attribute type in the graph and clean
 for(i in c("graph", "edge", "vertex")){
 g <- CleanNames(g, i)
 }

 return(g)

}

使用前面的示例

g4 <-union2(gList[[1]], gList[[2]])

#As we would like
get.edge.attribute(g4)
get.vertex.attribute(g4)