Find Consecutive Values in Vector in R

Find consecutive values in vector in R

Just use split in conjunction with diff:

> split(dat, cumsum(c(1, diff(dat) != 1)))
$`1`
[1] 1 2 3 4 5

$`2`
[1] 19 20 21

$`3`
[1] 56

$`4`
[1] 80 81

$`5`
[1] 92

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Not exactly what you asked for, but the "R.utils" package has a couple of related fun functions:

library(R.utils)
seqToIntervals(dat)
#      from to
# [1,]    1  5
# [2,]   19 21
# [3,]   56 56
# [4,]   80 81
# [5,]   92 92
seqToHumanReadable(dat)
# [1] "1-5, 19-21, 56, 80-81, 92"

How to check if a vector contains n consecutive numbers

Using diff and rle, something like this should work:

result <- rle(diff(numbers))
any(result$lengths>=2 & result$values==1)
# [1] TRUE

In response to the comments below, my previous answer was specifically only testing for runs of length==3 excluding longer lengths. Changing the == to >= fixes this. It also works for runs involving negative numbers:

> numbers4 <- c(-2, -1, 0, 5, 7, 8)
> result <- rle(diff(numbers4))
> any(result$lengths>=2 & result$values==1)
[1] TRUE

How Do I Find Consecutive Values

In case 1 1 1 1 means for you that 1 1 1 actually appears twice, you could do:

sum(stats::filter(x, c(1, 1, 1), circular = TRUE, sides = 2) == 3)

[1] 7

Count the number of consecutive occurrences in a vector

We can use rle and diff functions :

a=rle(diff(vec))
sum(a$values==1)

Create a list of vectors of consecutive values from a vector

An option is to split by creating a grouping variable created by checking the difference of adjacent elements

split(vec, cumsum(c(TRUE, diff(vec) != 1)))
#$`1`
#[1] 1 2

#$`2`
#[1] 5

#$`3`
#[1] 7 8 9

#$`4`
#[1] 11 12 13

#$`5`
#[1] 15

Determine sequence of consecutive numbers in R

Is this what you're after?

split(y, cumsum(c(0, diff(y) > 4)));
#$`0`
#[1]  4  8 12 16
#
#$`1`
#[1] 24
#
#$`2`
#[1] 31 33
#
#$`3`
#[1] 39
#
#$`4`
#[1] 64 68 72 76 80

I don't see 24 in your list; is that a mistake?

If you want to exclude list entries with only one number, you can do everything in one line:

Filter(length, lapply(split(y, cumsum(c(0, diff(y) > 4))), function(x) x[length(x) > 1]));
#$`0`
#[1]  4  8 12 16
#
#$`2`
#[1] 31 33
#
#$`4`
#[1] 64 68 72 76 80

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