问题与R“igraph”封装邻居功能 [英] issues with R "igraph" package neighbor function

问题描述

我最近开始使用Rigraph软件包（版本0.7）。我写了一个简单的程序来理解包的基本知识（将数据读入图对象，获得节点的邻居）。我正在使用其顶点从0开始的图形。图中的边缘会根据需要填充，但是当我尝试获取节点的邻接列表/邻居时，我发现它并没有给出我期望的结果。有人可以帮我解决这个问题吗？或者指出如果我缺少一些微不足道的东西？

下面是我写的图表数据/代码：

图形边缘数据（第一列包含第一个顶点，第二列包含第一个顶点有边的顶点）

  0 5 
 1 5 
 2 5 
 3 5 
 0 2 
 
>库（'igraph'）
> graph_file_ori = read.table（test.txt）
> graph_obj = graph.data.frame（graph_file_ori，directed = FALSE）
> str（graph_obj）
 IGRAPH UN  -  5 5  -  
 + attr：name（v / c）
 + edges（顶点名称）：
 
 [1 ] 0--5 1--5 2--5 3--5 0--2 
 
>邻居（graph_obj，0）
 .Call中的错误（R_igraph_neighbors，graph，as.igraph.vs（graph，v） -  1，：
在type_indexededgelist.c：750处：无法获取邻居，无效的顶点ID 
>邻居（graph_obj，1）
 [1] 3 5 
>邻居（graph_obj，2）
 [1] 5 
>邻居（graph_obj，3）
 [1] 1 5 
>邻居（graph_obj，4）
 [1] 5 
>邻居（graph_obj，5）
 [1] 1 2 3 4 
  

根据图表，预期产出为：

  neighbours（0）= 5,2 
 neighbors（1）= 5 
 neighbors（2）= 5， 0 
 neighbours（3）= 5 
  

4的等级为0.
欣赏帮助。

解决方案

如果您想使用符号顶点名称，那很好，但您需要使用它们你的查询也是如此。即写
$ b $ pre $ $ c $ neighbour（graph_obj，0）

如果您想要结果作为符号名称，那么你需要做的是

pre $ $ $ $ $ $ $ $ $ $ $ $ $ $ c>

从igraph版本0.8开始这将不再需要。

I started using the R "igraph" package recently(version 0.7). I wrote a simple program to understand the basics of the package(reading data into the graph object, getting the neighbours of a node). I am using a graph whose vertices start at 0. The edges in the graph are populated as I need it, however when I attempt to get the adjacency list/ neighbours of a node, I observed it was not giving the result that I expected. Can someone help me out with this/ or point out if I am missing something trivial ?

Below is the graph data/code that I wrote:

Graph Edge Data(first column contains the first vertex, second column contain the vertex to which there is an edge from the first vertex)

0 5
1 5
2 5
3 5
0 2

> library('igraph')
> graph_file_ori = read.table("test.txt")
> graph_obj = graph.data.frame(graph_file_ori,directed=FALSE)
> str(graph_obj)
IGRAPH UN-- 5 5 -- 
+ attr: name (v/c)
+ edges (vertex names):

[1] 0--5 1--5 2--5 3--5 0--2

> neighbors(graph_obj,0)
Error in .Call("R_igraph_neighbors", graph, as.igraph.vs(graph, v) - 1,  : 
At type_indexededgelist.c:750 : cannot get neighbors, Invalid vertex id
> neighbors(graph_obj,1)
[1] 3 5
> neighbors(graph_obj,2)
[1] 5
> neighbors(graph_obj,3)
[1] 1 5
> neighbors(graph_obj,4)
[1] 5
> neighbors(graph_obj,5)
[1] 1 2 3 4

Based on the graph, the expected output was :

neighbors(0) = 5,2
neighbors(1) = 5
neighbors(2) = 5,0
neighbors(3) = 5

Degree of 4 is 0. Appreciate the help.

解决方案

If you want to use symbolic vertex names, that is fine, but then you need to use them in your queries as well. I.e. write

neighbors(graph_obj, "0")

If you want the results as symbolic names as well, then you need to do

graph_obj$name[neighbors(graph_obj, "0")]

This will be not needed from igraph version 0.8.

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