组合边缘列表以common id为条件

Question

我想创建一个以id为条件的边缘列表 -

  combine = data.frame( id=  c(1,1,1,2,2,2,2) , pid = c("john","tom","dick","tom","harry","dick","sick"))

desired output:
person1 person2  id
john     tom      1
john     dick     1
tom      dick     1
tom     harry     2
tom     dick      2
..n so on

R中的代码是什么？

Answer 1

允许我稍微修改输入数据框以简化解决方案：

df <- data.frame(id = c(1,1,1,2,2,2,2), 
                 person = c("john","tom","dick","tom","harry","dick","sick"), 
                 stringsAsFactors = FALSE)

下一步是将数据框与自身合并：

dfe <- merge(x = df, y = df, by = "id", 
             suffixes = c("1", "2"))

唯一剩下的就是删除重复的边缘。这可以通过假设边缘按字母顺序排序来完成：

dfe <- dfe[dfe$person1 < dfe$person2,]

另外，我建议你阅读'igraph'包装。您要完成的大部分内容以及更多可用的内容。

Answer 2

我是这样做的

   library(tidyverse)
    combine = tibble( id=  c(1,1,1,2,2,2,2) , pid = c("john","tom","dick","tom","harry","dick","sick"))

    combo = function(x){

    combine %>% filter(id==x) %$% t(combn(pid,2)) %>% as_data_frame()%>% add_column(id=x)}
    map_df(unique(combine$id),combo) 
     V1    V2       id
  <chr> <chr> <dbl>
1 john  tom      1.
2 john  dick     1.
3 tom   dick     1.
4 tom   harry    2.
5 tom   dick     2.
6 tom   sick     2.
7 harry dick     2.
8 harry sick     2.
9 dick  sick     2.