使用sapply中的rep根据另一个向量拉伸向量
我想生成边的使用sapply中的rep根据另一个向量拉伸向量,r,apply,sapply,R,Apply,Sapply,我想生成边的data.frame。当多条边在一个节点上结束时会出现问题。边在向量from和to中定义 # Data vertices <- data.frame(id = 1:3, label = c("a", "b", "c"), stringsAsFactors = FALSE) to <- c("a", "b", "c") from1 <- c("c", "a", "b") from2 <- c("c", "a", "a,b,c") 但是,例如,从2开始的尝试失败
data.frame
。当多条边在一个节点上结束时会出现问题。边在向量from
和to
中定义
# Data
vertices <- data.frame(id = 1:3, label = c("a", "b", "c"), stringsAsFactors = FALSE)
to <- c("a", "b", "c")
from1 <- c("c", "a", "b")
from2 <- c("c", "a", "a,b,c")
但是,例如,从2开始的尝试失败
因此,我尝试了以下方法:
# Attempt 2
create_edges_2 <- function(from, to) {
to <- sapply(unlist(sapply(strsplit(to, ","), function(x){vertices$id[vertices$label == x]})), function(x){rep(x, sapply(strsplit(from2, ","), length))})
from <- unlist(sapply(strsplit(from2, ","), function(x){vertices$id[vertices$label == x]}))
data.frame(from = from, to = to, stringsAsFactors = FALSE)
}
这里有一个方法:
# Attempt 3
library(dplyr)
to <- sapply(to, function(x){vertices$id[vertices$label == x]})
from0 <- sapply(from2, function(x) strsplit(x, ",")) %>% unlist() %>% as.character()
lengths0 <- lapply(sapply(from2, function(x) strsplit(x, ",")), length) %>% unlist()
to0 <- c()
for( i in 1:length(lengths0)) to0 <- c(to0, rep(to[i], lengths0[i]))
from <- sapply(from0, function(x){vertices$id[vertices$label == x]})
edges <- data.frame(from = from, to = to0, stringsAsFactors = FALSE)
edges
其思想是使用逗号分隔符从
拆分,并存储每个元素的大小,以便“拉伸”每个节点。这里使用for
循环来完成您可以使用连接或匹配来完成此操作
f2 <- strsplit(from2, ',')
df <- data.frame(from = unlist(f2)
, to = rep(to, lengths(f2))
, stringsAsFactors = FALSE)
连接
library(dplyr)
df %>%
inner_join(vertices, by = c(from = 'label')) %>%
inner_join(vertices, by = c(to = 'label')) %>%
select_at(vars(matches('.x|.y')))
# id.x id.y
# 1 3 1
# 2 1 2
# 3 1 3
# 4 2 3
# 5 3 3
感谢您为我指出length
函数。rep(to,length(from))
部分是我头脑中缺失的一环
# Attempt 3
library(dplyr)
to <- sapply(to, function(x){vertices$id[vertices$label == x]})
from0 <- sapply(from2, function(x) strsplit(x, ",")) %>% unlist() %>% as.character()
lengths0 <- lapply(sapply(from2, function(x) strsplit(x, ",")), length) %>% unlist()
to0 <- c()
for( i in 1:length(lengths0)) to0 <- c(to0, rep(to[i], lengths0[i]))
from <- sapply(from0, function(x){vertices$id[vertices$label == x]})
edges <- data.frame(from = from, to = to0, stringsAsFactors = FALSE)
edges
from to
1 3 1
2 1 2
3 1 3
4 2 3
5 3 3
f2 <- strsplit(from2, ',')
df <- data.frame(from = unlist(f2)
, to = rep(to, lengths(f2))
, stringsAsFactors = FALSE)
library(tidyverse)
map_dfc(df, ~ with(vertices, id[match(.x, label)]))
# # A tibble: 5 x 2
# from to
# <int> <int>
# 1 3 1
# 2 1 2
# 3 1 3
# 4 2 3
# 5 3 3
library(dplyr)
df %>%
inner_join(vertices, by = c(from = 'label')) %>%
inner_join(vertices, by = c(to = 'label')) %>%
select_at(vars(matches('.x|.y')))
# id.x id.y
# 1 3 1
# 2 1 2
# 3 1 3
# 4 2 3
# 5 3 3