覆盖“不存在的组件”循环中

发布于 2025-01-09 17:24:12 字数 1081 浏览 0 评论 0原文

我有以下网络图：

library(tidyverse)
library(igraph)


set.seed(123)
n=15
data = tibble(d = paste(1:n))

relations = tibble(
  from = sample(data$d),
  to = lead(from, default=from[1]),
)

graph = graph_from_data_frame(relations, directed=T, vertices = data) 

V(graph)$color <- ifelse(data$d == relations$from[1], "red", "orange")

plot(graph, layout=layout.circle, edge.arrow.size = 0.2)

我学会了如何删除该图中的所有“边缘”：

g <- graph-E(graph)
plot(g)

现在，我正在尝试做同样的事情，但使用“循环”：

for (i in 1:15)
 for (j in 1:15) { 

graph <- graph - edge(paste0(i, "|", j)) 

}

但我认为问题在于上面的代码正在尝试删除存在的“边缘”，并且当命令该代码删除不存在的边缘时，此代码无法“跳过”（覆盖）实例：

Error in delete_edges(e1, unlist(e2, recursive = FALSE)) : 
  At iterators.c:1828 : Cannot create iterator, invalid edge id, Invalid vertex id

是否有一种方法可以指示此“循环” “跳过”两条边没有连接的每个实例并继续直到循环完成？

谢谢你！

原文

I have the following network graph:

library(tidyverse)
library(igraph)


set.seed(123)
n=15
data = tibble(d = paste(1:n))

relations = tibble(
  from = sample(data$d),
  to = lead(from, default=from[1]),
)

graph = graph_from_data_frame(relations, directed=T, vertices = data) 

V(graph)$color <- ifelse(data$d == relations$from[1], "red", "orange")

plot(graph, layout=layout.circle, edge.arrow.size = 0.2)

I learned how to remove all the "edges" in this graph:

g <- graph-E(graph)
plot(g)

Now, I am trying to do this same thing, but using a "loop" instead:

for (i in 1:15)
 for (j in 1:15) { 

graph <- graph - edge(paste0(i, "|", j)) 

}

But I think the problem is that the above code is trying to delete "edges" that exist, and this code does not have the ability to "skip" (override) an instance when it is commanded to delete a non-existing edge:

Error in delete_edges(e1, unlist(e2, recursive = FALSE)) : 
  At iterators.c:1828 : Cannot create iterator, invalid edge id, Invalid vertex id

Is there a way to instruct this "loop" to "skip" every instances where two edges do not have a connection and to continue until the loop is done?

Thank you!

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难以启齿的温柔 2025-01-16 17:24:12

我不知道您为什么要运行 for 循环，但请使用 igraph 中的 as_edgelist() 函数在下面找到一个可能的解决方案> 图书馆。

Reprex

您的数据

library(igraph)
library(dplyr)

set.seed(123)
n=15
data = tibble(d = paste(1:n))

relations = tibble(
  from = sample(data$d),
  to = lead(from, default=from[1]),
)

graph = graph_from_data_frame(relations, directed=T, vertices = data) 

V(graph)$color <- ifelse(data$d == relations$from[1], "red", "orange")

plot(graph, layout=layout.circle, edge.arrow.size = 0.2)

建议代码

edgelist <- as_edgelist(graph, names = TRUE)

  for (i in 1:15) { 
    
    graph <- graph - edge(paste0(edgelist[i,1], "|", edgelist[i,2])) 
    
  } 

plot(graph)

^{由 reprex 包 (v2.0.1)}

I don't know why you want to run a for loop, but please find below a possible solution using the as_edgelist() function from the igraph library.

Reprex

Your data

library(igraph)
library(dplyr)

set.seed(123)
n=15
data = tibble(d = paste(1:n))

relations = tibble(
  from = sample(data$d),
  to = lead(from, default=from[1]),
)

graph = graph_from_data_frame(relations, directed=T, vertices = data) 

V(graph)$color <- ifelse(data$d == relations$from[1], "red", "orange")

plot(graph, layout=layout.circle, edge.arrow.size = 0.2)

Suggested code

edgelist <- as_edgelist(graph, names = TRUE)

  for (i in 1:15) { 
    
    graph <- graph - edge(paste0(edgelist[i,1], "|", edgelist[i,2])) 
    
  } 

plot(graph)