这应该是一个足够简单的问题,但我真的不知道如何做到这一点。我有,说,图中的图形:
每个节点都有一个日期,我想找到出度最大的节点,只在日期在中位数之前的节点中。
我试过这个:
library(igraph)
nodes <- data.frame(name=c("a", "c", "d", "e", "f", "g", "i", "j", "k"),
date = c(27, 13, 0, 18, 0, 8, 44, 26, 22))
relations <- data.frame(from=c("d", "d", "f", "f","f", "g","g","g","c","c", "e"),
to=c("i", "f","d","c","g","k","a","c","a", "e","j"))
ggg <- graph.data.frame(relations, directed=TRUE, vertices=nodes)
V(ggg)$label <- V(ggg)$name
plot(ggg, layout = layout.fruchterman.reingold.grid, edge.curved=FALSE,
edge.arrow.size=0.2,edge.arrow.width=0.4)
V(ggg)$label <- V(ggg)$date
plot(ggg, layout = layout.fruchterman.reingold.grid, edge.curved=FALSE,
edge.arrow.size=0.2,edge.arrow.width=0.4)
median_delay <- median(V(ggg)$date)
vert_before_median <- V(ggg)[ V(ggg)$date <= median_delay ]
wnodes <- V(ggg)$name[ degree(ggg,v=vert_before_median,mode="out")==max(degree(ggg,v=vert_before_median,mode="out")) ]
到这里似乎一切正常:
> degree(ggg,v=vert_before_median,mode="out")==max(degree(ggg,v=vert_before_median,mode="out"))
c d e f g
FALSE FALSE FALSE TRUE TRUE
但是,当我想持有满足此属性的节点时,我遇到了麻烦。我以为
wnodes
应该包含节点“f”和“g”,而不是> wnodes
[1] "e" "f" "k"
似乎我在尝试从图中选择顶点的方式中遗漏了一些东西。我试过
which
,但还是不对:> V(ggg)[which( degree(ggg,v=vert_before_median,mode="out")==max(degree(ggg,v=vert_before_median,mode="out")) )]
Vertex sequence:
[1] "e" "f"
任何的想法?
最佳答案
子集 vert_before_median 而不是所有顶点,你应该得到你想要的,
wnodes <- vert_before_median[ degree(ggg,v=vert_before_median,mode="out")==max(degree(ggg,v=vert_before_median,mode="out")) ]
在上面的代码中,当您使用 R 对长度为 9 的所有顶点进行子集化时,R 会自动循环通过长度为 5(FALSE、FALSE、FALSE、TRUE、TRUE)的逻辑向量。
关于R iGraph : How to select vertices satisfying a certain rule,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37880105/