Count consecutive elements in a same length vector

Another option using rle and rep

with(rle(a), rep(lengths, times = lengths))
# [1] 2 2 3 3 3 4 4 4 4 2 2 3 3 3

data

a <- c(0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0)

Create a grouping variable using diff and use it in ave to calculate length of each group.

ave(x, cumsum(c(0, diff(x) != 0)), FUN = length)
# [1] 2 2 3 3 3 4 4 4 4 2 2 3 3 3

You can do the same with dplyr lag

library(dplyr)       
ave(x,cumsum(x != lag(x, default = FALSE)), FUN = length)
#[1] 2 2 3 3 3 4 4 4 4 2 2 3 3 3

And for completeness with data.table rleid

library(data.table)
ave(x, rleid(x), FUN = length)
#[1] 2 2 3 3 3 4 4 4 4 2 2 3 3 3

data

x <- c(0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0)

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