提问人：Discovery2020 提问时间：9/10/2023 最后编辑：MarkDiscovery2020 更新时间：9/10/2023 访问量：70
当行相等时，从 DataFrame 创建邻接矩阵
Make a adjacency matrix from dataframe when rows are equal
问：
我有一个类似于
mydf <- data.frame(Country=c('USA','Brazil','China','Italy','Ghana','Brazil','USA','China','USA'),
Pattern=c('XXZ','XXX','XYX','XXZ','XXX','XXX','XYZ','XXX','XYZ'),
Value=c(1,2,5,4,1,2,3,1,6))
如果 Pattern 的行相等，我需要一个无向邻接矩阵，这会添加值。
例如
From To Pattern Value
Brazil Brazil XXX 4
Brazil China XXX 3
Brazil Ghana XXX 3
答：
0赞
Mark
9/10/2023
#1
听起来你想要这个：
library(tidyverse)
mydf %>%
split(.$Pattern) %>%
map_dfr(~ .x %>%
mutate(n = row_number()) %>%
cross_join(., .) %>%
filter(n.x != n.y, Country.x <= Country.y) %>%
reframe(Value = `Value.x` + Value.y, .by = c(Country.x, Country.y)) %>%
rename(From = Country.x, To = Country.y) %>%
distinct(), .id = 'Pattern')
输出：
Pattern From To Value
1 XXX Brazil Ghana 3
2 XXX Brazil Brazil 4
3 XXX Brazil China 3
4 XXX China Ghana 2
5 XXZ Italy USA 5
6 XYZ USA USA 9
0赞
jay.sf
9/10/2023
#2
与案件处理一起使用。combnby
by(d, d$Pattern, \(x) {
u <- x$Country
out <- if (length(u) > 1) {
combn(u, 2, FUN=\(z) {
s <- x[x$Country %in% z, ]
if (length(table(z)) > 1) {
s <- unique(s)
}
with(s, data.frame(Country[1], Country[2], Pattern[1], sum(Value)))
}, simplify=FALSE) |> do.call(what='rbind') |> unique()
} else {
with(x, data.frame(Country, NA, Pattern, Value))
# with(x, data.frame(Country, NA, Pattern, NA)) ## alternatively
}
setNames(out, c('From', 'To', 'Pattern', 'Value'))
}) |> c(make.row.names=FALSE) |> do.call(what='rbind')
# From To Pattern Value
# 1 Brazil Ghana XXX 3
# 2 Brazil Brazil XXX 4
# 3 Brazil China XXX 3
# 4 Ghana China XXX 2
# 5 USA Italy XXZ 5
# 6 China <NA> XYX 5
# 7 USA USA XYZ 9
数据：
d <- structure(list(Country = c("USA", "Brazil", "China", "Italy",
"Ghana", "Brazil", "USA", "China", "USA"), Pattern = c("XXZ",
"XXX", "XYX", "XXZ", "XXX", "XXX", "XYZ", "XXX", "XYZ"), Value = c(1,
2, 5, 4, 1, 2, 3, 1, 6)), class = "data.frame", row.names = c(NA,
-9L))
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