使用类似以下示例的代码:

set.seed(11)
x <- sample(letters)
x
 [1] "h" "a" "m" "y" "b" "u" "v" "f" "p" "c" "q" "g" "x" "l" "i" "o" "e" "r" "t" "d" "z" "k" "s" "j" "w" "n"


并提供此值向量

y <- c(4, 13, 20)


我想将x向量除以y向量作为“切片”索引。并将结果分组为列表。所需的输出:

z <- list(c("h", "a", "m", "y"),c("b", "u", "v", "f", "p", "c", "q", "g", "x"), c("l", "i", "o", "e", "r", "t", "d"), c("z", "k", "s", "j", "w", "n") )
z
[[1]]
[1] "h" "a" "m" "y"

[[2]]
[1] "b" "u" "v" "f" "p" "c" "q" "g" "x"

[[3]]
[1] "l" "i" "o" "e" "r" "t" "d"

[[4]]
[1] "z" "k" "s" "j" "w" "n"

最佳答案

我们可以创建一个等于'x'长度的'0s'向量,使用y作为数字索引,将v1中的元素替换为1,cumsum结果并将其用作分组向量以分割'x'

v1 <- numeric(length(x))
v1[y+1] <- 1
split(x,cumsum(v1))


或者我们可以通过对cumsum的结果进行tabulate来获得分组向量

 split(x,cumsum(tabulate(y+1, length(x))))


或使用match

split(x,cumsum(c(TRUE,!is.na(match(seq_along(x), y)[-length(x)]))))


%in%

 split(x,cumsum(seq_along(x) %in% (y+1)))

关于r - R创建按索引划分的向量列表,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/29990401/

10-12 17:23
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