Hi Richard,
You could also do it using the package dplyr:
dta <- data.frame(Name=c('John','Mary','Sam','John'),
CheckInDate=as.Date(c('1/3/2014','1/3/2014','1/4/2014','1/4/2014'),
format='%d/%m/%Y'),
Temp=c(97,98.1,97.5,99))
library(dplyr)
dta %>% group_by(Name) %>% filter(CheckInDate==max(CheckInDate))
Source: local data frame [3 x 3]
Groups: Name
Name CheckInDate Temp
1 Mary 2014-03-01 98.1
2 Sam 2014-04-01 97.5
3 John 2014-04-01 99.0
On 24 January 2015 at 01:09, Chel Hee Lee <chl...@mail.usask.ca> wrote:
>> do.call(rbind, lapply(split(data, data$Name), function(x)
>> x[order(x$CheckInDate),][nrow(x),]))
> Name CheckInDate Temp
> John John 2014-04-01 99.0
> Mary Mary 2014-03-01 98.1
> Sam Sam 2014-04-01 97.5
>>
>
> Is this what you are looking for? I hope this helps.
>
> Chel Hee Lee
>
>
> On 01/23/2015 05:43 PM, Tan, Richard wrote:
>>
>> Hi,
>>
>> Can someone help for a R question?
>>
>> I have a data set like:
>>
>> Name CheckInDate Temp
>> John 1/3/2014 97
>> Mary 1/3/2014 98.1
>> Sam 1/4/2014 97.5
>> John 1/4/2014 99
>>
>> I'd like to return a dataset that for each Name, get the row that is the
>> latest CheckInDate for that person. For the example above it would be
>>
>> Name CheckInDate Temp
>> John 1/4/2014 99
>> Mary 1/3/2014 98.1
>> Sam 1/4/2014 97.5
>>
>>
>> Thank you for your help!
>>
>> Richard
>>
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@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.
>>
>
> ______________________________________________
> R-help@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.
______________________________________________
R-help@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.
