1. edgelist ⇔ graph

graph_from_edgelist() 
graph_from_data_frame()

as_data_frame(g)
as_edgelist(g)
get.edgelist(g)

注意， graph_from_data_frame 和as_data_frame 是可以将边的权重纳入进去的

2. adjacency matrix ⇔ graph

as_adjacency_matrix(g)

graph_from_adjacency_matrix()

3. edgelist ⇔ adjacency matrix

不通过graph转换也是可以的，使用pivot_wider 或者 pivot_longer

## EXAMPLE
library(tidyr)
fish_encounters %>%
    pivot_wider(names_from = station, values_from = seen, values_fill = 0) %>% tibble::column_to_rownames("fish")

或者使用reshape2::melt函数也可以实现