将向量分割成块 [英] Split a vector into chunks

问题描述

我必须在 R 中将一个向量分成 n 个大小相等的块.我找不到任何基本函数来做到这一点.谷歌也没有让我到任何地方.这是我目前想到的；

I have to split a vector into n chunks of equal size in R. I couldn't find any base function to do that. Also Google didn't get me anywhere. Here is what I came up with so far;

x <- 1:10
n <- 3
chunk <- function(x,n) split(x, factor(sort(rank(x)%%n)))
chunk(x,n)
$`0`
[1] 1 2 3

$`1`
[1] 4 5 6 7

$`2`
[1]  8  9 10

推荐答案

将 d 拆分为大小为 20 的块的单行式:

A one-liner splitting d into chunks of size 20:

split(d, ceiling(seq_along(d)/20))

更多细节:我认为你只需要seq_along()、split() 和ceiling():

More details: I think all you need is seq_along(), split() and ceiling():

> d <- rpois(73,5)
> d
 [1]  3  1 11  4  1  2  3  2  4 10 10  2  7  4  6  6  2  1  1  2  3  8  3 10  7  4
[27]  3  4  4  1  1  7  2  4  6  0  5  7  4  6  8  4  7 12  4  6  8  4  2  7  6  5
[53]  4  5  4  5  5  8  7  7  7  6  2  4  3  3  8 11  6  6  1  8  4
> max <- 20
> x <- seq_along(d)
> d1 <- split(d, ceiling(x/max))
> d1
$`1`
 [1]  3  1 11  4  1  2  3  2  4 10 10  2  7  4  6  6  2  1  1  2

$`2`
 [1]  3  8  3 10  7  4  3  4  4  1  1  7  2  4  6  0  5  7  4  6

$`3`
 [1]  8  4  7 12  4  6  8  4  2  7  6  5  4  5  4  5  5  8  7  7

$`4`
 [1]  7  6  2  4  3  3  8 11  6  6  1  8  4

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