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我正在分析存储由疾病模拟模型输出的数据的大表(300 000 - 500 000 行)。在模型中,景观中的动物会感染其他动物。例如,在下图中的示例中,动物 a1 感染景观上的每只动物,感染从动物转移到动物,分支为感染“链”。
在下面的示例中,我想获取存储有关每种动物的信息的表(在下面的示例中, table = allanimals
)并仅切出有关动物的信息 d2
的感染链(我以绿色突出显示 d2
的链),因此我可以计算该感染链的平均栖息地值。
虽然我的 while 循环有效,但当表存储数十万行并且链有 40-100 个成员时,它就像糖蜜一样缓慢。
关于如何加快速度的任何想法?希望有tidyverse
解决方案。我知道我的示例数据集“看起来足够快”,但我的数据确实很慢......
示意图:
以下示例数据的所需输出:
AnimalID InfectingAnimal habitat
1 d2 d1 1
2 d1 c3 1
3 c3 c2 3
4 c2 c1 2
5 c1 b3 3
6 b3 b2 6
7 b2 b1 5
8 b1 a2 4
9 a2 a1 2
10 a1 x 1
library(tidyverse)
# make some data
allanimals <- structure(list(AnimalID = c("a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8",
"b1", "b2", "b3", "b4", "b5", "c1", "c2", "c3", "c4", "d1", "d2", "e1", "e2",
"e3", "e4", "e5", "e6", "f1", "f2", "f3", "f4", "f5", "f6", "f7"),
InfectingAnimal = c("x", "a1", "a2", "a3", "a4", "a5", "a6", "a7", "a2", "b1",
"b2", "b3", "b4", "b3", "c1", "c2", "c3", "c3", "d1", "b1", "e1", "e2", "e3",
"e4", "e5", "e1", "f1", "f2", "f3", "f4", "f5", "f6"), habitat = c(1L, 2L, 1L,
2L, 2L, 1L, 3L, 2L, 4L, 5L, 6L, 1L, 2L, 3L, 2L, 3L, 2L, 1L, 1L, 2L, 5L, 4L,
1L, 1L, 1L, 1L, 4L, 5L, 4L, 5L, 4L, 3L)), .Names = c("AnimalID",
"InfectingAnimal", "habitat"), class = "data.frame", row.names = c(NA, -32L))
# check it out
head(allanimals)
# Start with animal I'm interested in - say, d2
Focal.Animal <- "d2"
# Make a 1-row data.frame with d2's information
Focal.Animal <- allanimals %>%
filter(AnimalID == Focal.Animal)
# This is the animal we start with
Focal.Animal
# Make a new data.frame to store our results of the while loop in
Chain <- Focal.Animal
# make a condition to help while loop
InfectingAnimalInTable <- TRUE
# time it
ptm <- proc.time()
# Run loop until you find an animal that isn't in the table, then stop
while(InfectingAnimalInTable == TRUE){
# Who is the next infecting animal?
NextAnimal <- Chain %>%
slice(n()) %>%
select(InfectingAnimal) %>%
unlist()
NextRow <- allanimals %>%
filter(AnimalID == NextAnimal)
# If there is an infecting animal in the table,
if (nrow(NextRow) > 0) {
# Add this to the Chain table
Chain[(nrow(Chain)+1),] <- NextRow
#Otherwise, if there is no infecting animal in the table,
# define the Infecting animal follows, this will stop the loop.
} else {InfectingAnimalInTable <- FALSE}
}
proc.time() - ptm
# did it work? Check out the Chain data.frame
Chain
最佳答案
所以这里的问题在于你的数据结构。您将需要一个向量来存储谁被谁感染(将谁保留为整数):
allanimals_ID <- unique(c(allanimals$AnimalID, allanimals$InfectingAnimal))
infected <- rep(NA_integer_, length(allanimals_ID))
infected[match(allanimals$AnimalID, allanimals_ID)] <-
match(allanimals$InfectingAnimal, allanimals_ID)
path <- rep(NA_integer_, length(allanimals_ID))
curOne <- match("d2", allanimals_ID)
i <- 1
while (!is.na(nextOne <- infected[curOne])) {
path[i] <- curOne
i <- i + 1
curOne <- nextOne
}
allanimals[path[seq_len(i - 1)], ]
关于r - 在 R 中查找感染链的方法比 "while"循环更快,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45865242/
根据我的研究,我发现 AWS SDK CPP 允许 upload/download files到桶。 我需要在 AWS EBS 上拥有相同的上传/下载访问权限 st1 类型的卷,但我找不到任何关于它的
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