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-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
Behalf Of Muhuri, Pradip (SAMHSA/CBHSQ)
Sent: Sunday, November 09, 2014 6:11 AM
To: 'Mark Sharp'
Cc: r-help@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:msh...@txbiomed.org]
Sent: Sunday, November 09, 2014 3:01 AM
To: Muhuri, Pradip (SAMHSA/CBHSQ)
Cc: r-help@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: msh...@txbiomed.org
NOTICE: This E-Mail (including attachments) is confidential and may be legally
privileged. It is covered by the Electronic Communications Privacy Act, 18
U.S.C.2510-2521. If you are not the intended recipient, you are hereby
notified that any retention, dissemination, distribution or copying of this
communication is strictly prohibited. Please reply to the sender that you have
received this message in error, then delete it.
______________________________________________
R-help@r-project.org mailing list
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.
