[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)
Chel Hee Lee
chl948 at mail.usask.ca
Thu Dec 4 02:48:00 CET 2014
The output in the object 'new1' are apparently same the output in the
object 'new2'. Are you trying to compare the entries of two outputs
'new1' and 'new2'? If so, the function 'all()' would be useful:
> all(new1 == new2, na.rm=TRUE)
[1] TRUE
If you are interested in the comparison of two objects in terms of
class, then the function 'identical()' is useful:
> attributes(new1)
$names
[1] "id" "mrjdate" "cocdate" "inhdate" "haldate" "oldflag"
$class
[1] "rowwise_df" "tbl_df" "tbl" "data.frame"
$row.names
[1] 1 2 3 4 5 6 7
> attributes(new2)
$names
[1] "id" "mrjdate" "cocdate" "inhdate" "haldate" "oiddate"
$row.names
[1] 1 2 3 4 5 6 7
$class
[1] "data.frame"
I hope this helps.
Chel Hee Lee
On 12/03/2014 04:10 PM, Muhuri, Pradip (SAMHSA/CBHSQ) wrote:
> Hello,
>
> Two alternative approaches - mutate() vs. sapply() - were used to get the desired results (i.e., creating a new column of the most recent date from 4 dates ) with help from Arun and Mark on this forum. I now find that the two data objects (created using two different approaches) are not identical although results are exactly the same.
>
> identical(new1, new2)
> [1] FALSE
>
> Please see the reproducible example below.
>
> I don't understand why the code returns FALSE here. Any hints/comments will be appreciated.
>
> Thanks,
>
> Pradip
>
> ############################################# reproducible example ########################################
> library(dplyr)
> # data object - description
>
> temp <- "id mrjdate cocdate inhdate haldate
> 1 2004-11-04 2008-07-18 2005-07-07 2007-11-07
> 2 NA NA NA NA
> 3 2009-10-24 NA 2011-10-13 NA
> 4 2007-10-10 NA NA NA
> 5 2006-09-01 2005-08-10 NA NA
> 6 2007-09-04 2011-10-05 NA NA
> 7 2005-10-25 NA NA 2011-11-04"
>
> # read the data object
>
> example.data <- read.table(textConnection(temp),
> colClasses=c("character", "Date", "Date", "Date", "Date"),
> header=TRUE, as.is=TRUE
> )
>
>
> # create a new column -dplyr solution (Acknowledgement: Arun)
>
> new1 <- example.data %>%
> rowwise() %>%
> mutate(oldflag=as.Date(max(mrjdate,cocdate, inhdate, haldate,
> na.rm=TRUE), origin='1970-01-01'))
>
> # create a new column - Base R solution (Acknowlegement: Mark Sharp)
>
> new2 <- example.data
> new2$oiddate <- as.Date(sapply(seq_along(new2$id), function(row) {
> if (all(is.na(unlist(example.data[row, c('mrjdate','cocdate', 'inhdate', 'haldate')])))) {
> max_d <- NA
> } else {
> max_d <- max(unlist(example.data[row, c('mrjdate','cocdate', 'inhdate', 'haldate')]), na.rm = TRUE)
> }
> max_d}),
> origin = "1970-01-01")
>
> identical(new1, new2)
>
> # print records
>
> print (new1); print(new2)
>
> Pradip K. Muhuri
> SAMHSA/CBHSQ
> 1 Choke Cherry Road, Room 2-1071
> Rockville, MD 20857
> Tel: 240-276-1070
> Fax: 240-276-1260
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Muhuri, Pradip (SAMHSA/CBHSQ)
> Sent: Sunday, November 09, 2014 6:11 AM
> To: 'Mark Sharp'
> Cc: r-help at r-project.org
> Subject: Re: [R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)
>
> Hi Mark,
>
> Your code has also given me the results I expected. Thank you so much for your help.
>
> Regards,
>
> Pradip
>
> Pradip K. Muhuri, PhD
> SAMHSA/CBHSQ
> 1 Choke Cherry Road, Room 2-1071
> Rockville, MD 20857
> Tel: 240-276-1070
> Fax: 240-276-1260
>
>
> -----Original Message-----
> From: Mark Sharp [mailto:msharp at TxBiomed.org]
> Sent: Sunday, November 09, 2014 3:01 AM
> To: Muhuri, Pradip (SAMHSA/CBHSQ)
> Cc: r-help at r-project.org
> Subject: Re: [R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)
>
> Pradip,
>
> mutate() works on the entire column as a vector so that you find the maximum of the entire data set.
>
> I am almost certain there is some nice way to handle this, but the sapply() function is a standard approach.
>
> max() does not want a dataframe thus the use of unlist().
>
> Using your definition of data1:
>
> data3 <- data1
> data3$oidflag <- as.Date(sapply(seq_along(data3$id), function(row) {
> if (all(is.na(unlist(data1[row, -1])))) {
> max_d <- NA
> } else {
> max_d <- max(unlist(data1[row, -1]), na.rm = TRUE)
> }
> max_d}),
> origin = "1970-01-01")
>
> data3
> id mrjdate cocdate inhdate haldate oidflag
> 1 1 2004-11-04 2008-07-18 2005-07-07 2007-11-07 2008-07-18
> 2 2 <NA> <NA> <NA> <NA> <NA>
> 3 3 2009-10-24 <NA> 2011-10-13 <NA> 2011-10-13
> 4 4 2007-10-10 <NA> <NA> <NA> 2007-10-10
> 5 5 2006-09-01 2005-08-10 <NA> <NA> 2006-09-01
> 6 6 2007-09-04 2011-10-05 <NA> <NA> 2011-10-05
> 7 7 2005-10-25 <NA> <NA> 2011-11-04 2011-11-04
>
>
>
> R. Mark Sharp, Ph.D.
> Director of Primate Records Database
> Southwest National Primate Research Center Texas Biomedical Research Institute P.O. Box 760549 San Antonio, TX 78245-0549
> Telephone: (210)258-9476
> e-mail: msharp at TxBiomed.org
>
>
>
>
>
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