матрица смежности R

Question

Как я могу преобразовать список ребер в матрицу смежности в R?

Ввод выглядит следующим образом:

from           to
Kanye West     Jay-Z
Beyonce        Nicki Minaj
Kid Cudi       Chance The Rapper

Answer 1

Вот две разные возможности:

Метод 1

Использование igraph::get.adjacency

# Convert data.frame to igraph
library(igraph);
ig <- graph_from_data_frame(df);

# Get adjacency matrix
get.adjacency(ig);
#6 x 6 sparse Matrix of class "dgCMatrix"
#                  Kanye West Beyonce Kid Cudi Jay-Z Nicki Minaj
#Kanye West                 .       .        .     1           .
#Beyonce                    .       .        .     .           1
#Kid Cudi                   .       .        .     .           .
#Jay-Z                      .       .        .     .           .
#Nicki Minaj                .       .        .     .           .
#Chance The Rapper          .       .        .     .           .
#                  Chance The Rapper
#Kanye West                        .
#Beyonce                           .
#Kid Cudi                          1
#Jay-Z                             .
#Nicki Minaj                       .
#Chance The Rapper                 .

Метод 2

Использование reshape2::dcast

library(reshape2);
df$from <- factor(df$from, levels = unique(as.character(unlist(df))))
df$to <- factor(df$to, levels = unique(as.character(unlist(df))))
dcast(df, from ~ to, fun.aggregate = length, drop = F);
#               from Kanye West Beyonce Kid Cudi Jay-Z Nicki Minaj
#1        Kanye West          0       0        0     1           0
#2           Beyonce          0       0        0     0           1
#3          Kid Cudi          0       0        0     0           0
#4             Jay-Z          0       0        0     0           0
#5       Nicki Minaj          0       0        0     0           0
#6 Chance The Rapper          0       0        0     0           0
#  Chance The Rapper
#1                 0
#2                 0
#3                 1
#4                 0
#5                 0
#6                 0

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Пример данных

# Sample data
df <- read.table(text =
    "from           to
'Kanye West'     'Jay-Z'
'Beyonce'        'Nicki Minaj'
'Kid Cudi'       'Chance The Rapper'", header = T)