[R] Identifying and characterizing strings of NA in a vector

[Dimitris Rizopoulos]

try something like this:

vec <- c(1, 2, 1, NA, NA, 1, 2, NA, NA, NA, 3, 4, NA, NA)

out <- rle(is.na(vec))
table(out$lengths[out$values])


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Marie-Pierre Sylvestre" <marie-pierre.sylvestre at mail.mcgill.ca>
To: <r-help at r-project.org>
Sent: Thursday, October 11, 2007 3:47 PM
Subject: [R] Identifying and characterizing strings of NA in a vector


> Dear R users,
>
> I was wondering if someone could suggest a few lines of code for my 
> problem.
>
> I want to count the number and the length of strings of NA in a 
> vector.
> For example:
>
> vec <- c(1, 2, 1, NA, NA, 1, 2, NA, NA, NA, 3, 4, NA, NA)
>
> has 2 strings of NA's of length 2 and 1 string of NA' of length 3.
>
> I can easily count the number of NA's per vector, but I am having a 
> hard
> time counting the number and length of strings of NA's per vector
> without relying heavily on loops. I will have to perform this task 
> for
> many vectors.
>
> Can somebody help?
>
> many thanks,
>
> Marie-Pierre
>
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> and provide commented, minimal, self-contained, reproducible code.
> 


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