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Muhuri, Pradip (SAMHSA/CBHSQ)

2014-Dec-03 22:10 UTC

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

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





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 at 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.

David Winsemius

2014-Dec-04 01:14 UTC

head link

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

On Dec 3, 2014, at 2:10 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
> 
You should have examined the output from dput() on both objects. I think you
will find that dplyr is adding new attributes.

Notice the the "mutate()-ed" object now has this class:

class = c("rowwise_df", "tbl_df", "tbl",
"data.frame")

Moral: Never rely on the the print representation.

-- 
David.

> 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
> 
> 
> 
> 
> 
> 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 at 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 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.
David Winsemius
Alameda, CA, USA

Chel Hee Lee

2014-Dec-04 01:48 UTC

head link

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

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
>
>
>
>
>
> 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 at 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 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.
>

Muhuri, Pradip (SAMHSA/CBHSQ)

2014-Dec-04 03:43 UTC

head link

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

Hello Chel and David,

Thank you very much for providing new insights into this issue.  Here is one
more question.  Why  does the mutate () give incorrect results here?

# The following gives INCORRECT results - mutated()ed object
na.date.cases = ifelse(!is.na(oiddate),1,0)

# The following gives CORRECT results
new2$na.date.cases = ifelse(!is.na(new2$oiddate),1,0)

###############################  reproducible example - slightly
revised/modified  ###############
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(oiddate=as.Date(max(mrjdate,cocdate, inhdate, haldate, na.rm=TRUE),
origin='1970-01-01'),
             na.date.cases = ifelse(!is.na(oiddate),1,0)
             )

# 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")

new2$na.date.cases = ifelse(!is.na(new2$oiddate),1,0)


identical(new1, new2) 

table(new1$oiddate)
table(new2$oiddate)

# print records

print (new1); print(new2)

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: Chel Hee Lee [mailto:chl948 at mail.usask.ca] 
Sent: Wednesday, December 03, 2014 8:48 PM
To: Muhuri, Pradip (SAMHSA/CBHSQ); 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)

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
>
>
>
>
>
> 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
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> ______________________________________________
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> PLEASE do read the posting guide 
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> and provide commented, minimal, self-contained, reproducible code.
>
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>

R help - Dec 2014 - Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)

[R] Getting the most recent dates in a new column from dates in four columns using the dplyr package (mutate verb)