R 中的 igraph - 合并两个图

Question

我正在尝试使用 igraph 在 R 中合并两个图。理想情况下，我会创建一个来自 g1 和 g2 的顶点并集，只保留来自 g1 的边。这个联合应该基于 label 属性创建。我想我可以在合并之前简单地删除 g2 中的所有边，使用类似这样的东西：

g2 %>% delete_edges(seq(1, length(E(g2)), by = 1))

不过，当我创建这样的联合时：

g.union <- graph.union(g1, g2, byname=F)

我得到一个具有属性 id_1、id_2、label_1、label_2、weight_1、weight_2... 的图表不是我想要的。我需要保留 g1 中的所有顶点和边，只添加 g2 中 g1 中缺失的那些顶点。保留那些添加的顶点的所有属性。

感谢任何帮助！

编辑：

@MrFlick，我不能分享这些图表，但一个简单的例子是这样的：

我有g1

graph
[
  directed 1
  node
  [
    id 1
    label "it2igcryfm862x"
    mydetails "somedetails1"
  ]
  node
  [
    id 2
    label "it0l2xa53eu1w3"
    mydetails "somedetails2"
  ]
  node
  [
    id 3
    label "iszyxcopnao380"
    mydetails "somedetails3"
  ]
 edge
  [
    source 1
    target 2
    weight 1
  ]
  edge
  [
    source 1
    target 3
    weight 2
  ]
  edge
  [
    source 2
    target 3
    weight 1
  ]
]

和g2

graph
[
  directed 1
  node
  [
    id 1
    label "it2igcryfm862x"
    mydetails "somedetails1"
  ]
  node
  [
    id 2
    label "it0l2xa53eu1w3"
    mydetails "somedetails2"
  ]
  node
  [
    id 3
    label "iszyxcopnao380"
    mydetails "somedetails3"
  ]
  node
  [
    id 4
    label "it0lhztmkln4n6"
    mydetails "somedetails4"
  ]
 edge
  [
    source 1
    target 2
    weight 1
  ]
  edge
  [
    source 1
    target 3
    weight 3
  ]
  edge
  [
    source 2
    target 3
    weight 2
  ]
  edge
  [
    source 2
    target 4
    weight 2
  ]
  edge
  [
    source 3
    target 4
    weight 1
  ]
]

而我需要的是g3

graph
[
  directed 1
  node
  [
    id 1
    label "it2igcryfm862x"
    mydetails "somedetails1"
  ]
  node
  [
    id 2
    label "it0l2xa53eu1w3"
    mydetails "somedetails2"
  ]
  node
  [
    id 3
    label "iszyxcopnao380"
    mydetails "somedetails3"
  ]
  node
  [
    id 4
    label "it0lhztmkln4n6"
    mydetails "somedetails4"
  ]
 edge
  [
    source 1
    target 2
    weight 1
  ]
  edge
  [
    source 1
    target 3
    weight 2
  ]
  edge
  [
    source 2
    target 3
    weight 1
  ]
]

Answer 1

这是一个可重现的例子

library(igraph)
set.seed(1)
g1 <- make_(ring(10), with_vertex_(label = LETTERS[1:10]))
V(g1)$color = "red"
g2 <- make_(ring(15), with_vertex_(label = LETTERS[1:15]))
V(g2)$color <- "cyan"

你需要

retain all the vertices and edges from g1 adding only those vertices from g2 that are missing in g1. Keeping all properties of those added vertices.

一种方法：

v <- V(g2)[!V(g2)%in%V(g1)]
g3 <- add_vertices(g1, length(v), attr = vertex.attributes(g2, v))

下面是两个原始图表和结果的样子：

par(mfrow=c(1,3))
lapply(mget(ls(pattern = "^g\d")), plot)

Answer 2

您的原始代码似乎接近处理您提供的示例。

library(igraph)

###  Recreating your example
par(mfrow = c(2,2), mar=c(0.5,0.5,0.5,0.5))
g1 = graph_from_edgelist(matrix(c(1,2,1,3,2,3), ncol=2, byrow=TRUE))
g1 = set_vertex_attr(g1, "label", 
    value=c("it2igcryfm862x", "it0l2xa53eu1w3", 
        "iszyxcopnao380"))
plot(g1)
box()

g2 = graph_from_edgelist(matrix(c(1,2,1,3,2,3,2,4,3,4), ncol=2, byrow=TRUE))
g2 = set_vertex_attr(g2, "label", 
    value=c("it2igcryfm862x", "it0l2xa53eu1w3", 
        "iszyxcopnao380", "it0lhztmkln4n6"))
plot(g2)
box()

## Create the desired union
g1g2 = union(g1,delete_edges(g2, E(g2)))

## Edit: Preserving labels
NewLabels = c(vertex_attr(g1, "label"), 
    setdiff(vertex_attr(g2, "label"), vertex_attr(g1, "label")))
g1g2 = set_vertex_attr(g1g2, "label", value=NewLabels)

plot(g1g2)
box()

R 中的 igraph - 合并两个图

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