CODEWITHSUNDEEP
rlistvectormergesplit
Daniel James
Daniel James

Reputation: 1433

Split a Parent Vector to Overlapping Sub-vectors with Equal seb-vectors Length Except the Last Sub-vector in R

I want to split a parent vector into subvectors of equal lengths and overlapping suvectors such that if there exists a supposed last vector who would not make the specified subvector length to be merged with its penultimate. This question is a follow-up from @rawr comment HERE

########Block function######################
blocks <- function(len, ov, n) {

  starts <- unique(sort(c(seq(1, n, len), seq(len-ov+1, n, len))))
  ends <- pmin(starts + len - 1, n)

  # truncate starts and ends to the first num elements
  num <- match(n, ends)
  head(data.frame(starts, ends), num)
}

########Moving block#############
vec = 1:17
len = 8
ov = ceiling(len/2)
b <- blocks(len, ov, length(vec))
with(b, Map(function(i, j) vec[i:j], starts, ends))

1 1 2 3 4 5 6 7 8

[2] 5 6 7 8 9 10 11 12

[3] 9 10 11 12 13 14 15 16

[4] 13 14 15 16 17

What I want

I want the last list that is not up to the specified subvector to be merged to the penultimate list like this:

1 1 2 3 4 5 6 7 8

[2] 5 6 7 8 9 10 11 12

[3] 9 10 11 12 13 14 15 16 13 14 15 16 17

Upvotes: 1

Views: 49

Answers (1)

akrun
akrun

Reputation: 887153

We can create a condition with if

out <- with(b, Map(function(i, j) vec[i:j], starts, ends))
l1 <- length(out)
if(length(out[[l1]]) < len) {
    out[[l1-1]] <- unlist(out[(l1-1):l1])
    out[[l1]] <- NULL
}

-output

out
[[1]]
[1] 1 2 3 4 5 6 7 8

[[2]]
[1]  5  6  7  8  9 10 11 12

[[3]]
 [1]  9 10 11 12 13 14 15 16 13 14 15 16 17

Upvotes: 1

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