# [R] number of individuals where X=0 during all periods (longitudinal data)

Barry Rowlingson b.rowlingson at lancaster.ac.uk
Tue Dec 23 09:24:13 CET 2014

```obligatory dplyr solution:

library(dplyr)
zeroes = Test %>% group_by(ID) %>% summarise(Zs=all(X==0))

- that gives you a data frame of unique ID and Zs==TRUE if that ID
has all zeroes. With that you just sum(zeroes\$Zs) to get the total
number with all zeroes. Or add "%>% filter(Zs) %>% nrow()" to the
pipeline to get it directly.

Its well worth learning a bit about the dplyr and tidyr package,
especially if you have a lot of things you might want to do by ID in a
data frame.

Barry

On Mon, Dec 22, 2014 at 7:52 PM, William Dunlap <wdunlap at tibco.com> wrote:
> Another approach to to make a table and extract your summaries from the
> table:
>
>   > tbl <- with(Test, table(ID, IsZero=X==0))
>   > tbl
>      IsZero
>   ID  FALSE TRUE
>     1     3    1
>     2     0    2
>     3     0    3
>   > sum(tbl[,"FALSE"] == 0)
>   [1] 2
>   > sum(tbl[,"FALSE"] == 0 & rowSums(tbl)>=3)
>   [1] 1
>
> Remove the calls to sum() from those expressions and you will see which
> ID's satisfy the conditions.
>
>
>
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
>
> On Mon, Dec 22, 2014 at 10:54 AM, Chel Hee Lee <chl948 at mail.usask.ca> wrote:
>>
>> > tmp <- split(Test, Test\$ID)
>> >
>> > # number of subjects with X=0 (all periods)
>> > x <- lapply(tmp, function(x) all(x\$X ==0))
>> > length(x[unlist(x)])
>> [1] 2
>> >
>> > # number of subjects with X=0 (at least three weeks)
>> > x <- lapply(tmp, function(x) sum(x\$X==0)>=3)
>> > length(x[unlist(x)])
>> [1] 1
>> >
>>
>> Is this what you are looking for?  I hope this helps.
>>
>> Chel Hee Lee
>>
>> On 12/22/2014 7:45 AM, najuzz wrote:
>>
>>> #Hi guys,
>>>
>>> #I would like to count the number of individuals that receive X=0
>>> troughout
>>> their observational period.
>>> #example dataset:
>>>
>>> ID<-c(1,1,1,1,2,2,3,3,3)
>>> X<-c(0,1,2,1,0,0,0,0,0)
>>> Time<-c(1,2,3,4,1,2,1,2,3)
>>> Test<-data.frame(ID,X,Time)
>>>
>>> # Individuals 2 and 3 have x=0 during all their periods. The count should
>>> hence equal to two. I simply have
>>> # no clue how R could solve this for me. As an addon, I would also like to
>>> know the number of individuals  #that report X=0 during all periods plus
>>> have at least 3 weeks of observations. The answer would be one in #this
>>> sample datset.
>>>
>>> #Thank you
>>>
>>>
>>>
>>> --
>>> View this message in context: http://r.789695.n4.nabble.com/
>>> number-of-individuals-where-X-0-during-all-periods-
>>> longitudinal-data-tp4701023.html
>>> Sent from the R help mailing list archive at Nabble.com.
>>>
>>> ______________________________________________
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>>>
>>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/
>> posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

```