分裂矢量与R中的重叠样本

Question

假设我有一个具有1000个值的向量,我想将此向量"拆分/分区/分组"为多个向量,每个向量具有200个值,并且它们之间有100个值的重叠.

例如:

vec = seq(1,1000)
splitWithOverlap(vec, 200, 100)

应该返回以下向量:

[0:200] [100:300] [200:400] [300:500] ...

......你明白了.

R中是否有一个函数可以用来做到这一点？

Answer 1

rollapply创建一个矩阵,m其行是所需的向量.如果这样的结果足够,那么在那一点上停止省略最后一行代码; 否则,如果需要向量列表,请按行拆分:

library(zoo)

x <- 1:1000  # test input

m <- rollapply(x, 200, by = 100, c)
split(m, row(m))

Answer 2

不,但这样做会:

splitWithOverlap <- function(vec, seg.length, overlap) {
  starts = seq(1, length(vec), by=seg.length-overlap)
  ends   = starts + seg.length - 1
  ends[ends > length(vec)] = length(vec)

  lapply(1:length(starts), function(i) vec[starts[i]:ends[i]])
}

> splitWithOverlap(1:100, 20, 10)
[[1]]
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20

[[2]]
 [1] 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

[[3]]
 [1] 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

[[4]]
 [1] 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

[[5]]
 [1] 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

[[6]]
 [1] 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

[[7]]
 [1] 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

[[8]]
 [1] 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

[[9]]
 [1]  81  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96  97  98  99 100

[[10]]
 [1]  91  92  93  94  95  96  97  98  99 100