R help - Oct 2017 - Populate one data frame with values from another dataframe for rows that match

I'm trying to populate the column ?pf_mcl? in myDF1 with values from myDF2,
where rows match based on column "studyno" but the solutions I have
found so far don't seem to be giving me the desired output.

Below is a snapshot of the data.frames.

myDF1 <- structure(list(studyno = c("J1000/9", "J1000/9",
"J1000/9", "J1000/9",
"J1000/9", "J1000/9"), date = structure(c(17123, 17127,
17135,
17144, 17148, 17155), class = "Date"), pf_mcl = c(NA_integer_,
NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_
), year = c(2016, 2016, 2016, 2016, 2016, 2016)), .Names =
c("studyno",
"date", "pf_mcl", "year"), row.names = c(NA, 6L),
class = "data.frame")

myDF2 <- structure(list(studyno = c("J740/4", "J1000/9",
"J895/7", "J931/6",
"J609/1", "J941/3"), pf_mcl = c(0L, 0L, 0L, 0L, 0L, 0L)),
.Names = c("studyno",
"pf_mcl"), row.names = c(NA, 6L), class = "data.frame")

myDF2 is a well curated subset of myDF1. Some rows in the two datasets match
based on "studyno", one may find that values are missing in
myDF1$pf_mcl or the values are wrong.

All I want to do is identify a matching row in myDF2 and populate myDF1$pf_mcl
with the value in myDF2$pf_mcl. If a row does not match based on ?studyno?, the
value should remain the same.

It's probably worth mentioning, the two data frames have other columns...I
have selected a few for example purposes.



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?merge

Bert

On Oct 13, 2017 12:09 PM, "Kevin Wamae" <KWamae at
kemri-wellcome.org> wrote:
> I'm trying to populate the column ?pf_mcl? in myDF1 with values from
> myDF2, where rows match based on column "studyno" but the
solutions I have
> found so far don't seem to be giving me the desired output.
>
> Below is a snapshot of the data.frames.
>
> myDF1 <- structure(list(studyno = c("J1000/9",
"J1000/9", "J1000/9",
> "J1000/9",
> "J1000/9", "J1000/9"), date = structure(c(17123, 17127,
17135,
> 17144, 17148, 17155), class = "Date"), pf_mcl = c(NA_integer_,
> NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_
> ), year = c(2016, 2016, 2016, 2016, 2016, 2016)), .Names =
c("studyno",
> "date", "pf_mcl", "year"), row.names = c(NA,
6L), class = "data.frame")
>
> myDF2 <- structure(list(studyno = c("J740/4",
"J1000/9", "J895/7",
> "J931/6",
> "J609/1", "J941/3"), pf_mcl = c(0L, 0L, 0L, 0L, 0L,
0L)), .Names > c("studyno",
> "pf_mcl"), row.names = c(NA, 6L), class = "data.frame")
>
> myDF2 is a well curated subset of myDF1. Some rows in the two datasets
> match based on "studyno", one may find that values are missing in
> myDF1$pf_mcl or the values are wrong.
>
> All I want to do is identify a matching row in myDF2 and populate
> myDF1$pf_mcl with the value in myDF2$pf_mcl. If a row does not match based
> on ?studyno?, the value should remain the same.
>
> It's probably worth mentioning, the two data frames have other
columns...I
> have selected a few for example purposes.
>
>
>
> ______________________________________________________________________
>
> This e-mail contains information which is confidential. It is intended
> only for the use of the named recipient. If you have received this e-mail
> in error, please let us know by replying to the sender, and immediately
> delete it from your system.  Please note, that in these circumstances, the
> use, disclosure, distribution or copying of this information is strictly
> prohibited. KEMRI-Wellcome Trust Programme cannot accept any responsibility
> for the  accuracy or completeness of this message as it has been
> transmitted over a public network. Although the Programme has taken
> reasonable precautions to ensure no viruses are present in emails, it
> cannot accept responsibility for any loss or damage arising from the use of
> the email or attachments. Any views expressed in this message are those of
> the individual sender, except where the sender specifically states them to
> be the views of KEMRI-Wellcome Trust Programme.
> ______________________________________________________________________
>
>         [[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.
	[[alternative HTML version deleted]]

Hello,

Try the following.


myDF1$studyno <- as.character(myDF1$studyno)
myDF2$studyno <- as.character(myDF2$studyno)
i1 <- which(names(myDF1) == "pf_mcl")

merge(myDF1[-i1], myDF2, by = "studyno")


Hope this helps,

Rui Barradas

Em 13-10-2017 20:09, Kevin Wamae escreveu:
> I'm trying to populate the column ?pf_mcl? in myDF1 with values from
myDF2, where rows match based on column "studyno" but the solutions I
have found so far don't seem to be giving me the desired output.
>
> Below is a snapshot of the data.frames.
>
> myDF1 <- structure(list(studyno = c("J1000/9",
"J1000/9", "J1000/9", "J1000/9",
> "J1000/9", "J1000/9"), date = structure(c(17123, 17127,
17135,
> 17144, 17148, 17155), class = "Date"), pf_mcl = c(NA_integer_,
> NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_
> ), year = c(2016, 2016, 2016, 2016, 2016, 2016)), .Names =
c("studyno",
> "date", "pf_mcl", "year"), row.names = c(NA,
6L), class = "data.frame")
>
> myDF2 <- structure(list(studyno = c("J740/4",
"J1000/9", "J895/7", "J931/6",
> "J609/1", "J941/3"), pf_mcl = c(0L, 0L, 0L, 0L, 0L,
0L)), .Names = c("studyno",
> "pf_mcl"), row.names = c(NA, 6L), class = "data.frame")
>
> myDF2 is a well curated subset of myDF1. Some rows in the two datasets
match based on "studyno", one may find that values are missing in
myDF1$pf_mcl or the values are wrong.
>
> All I want to do is identify a matching row in myDF2 and populate
myDF1$pf_mcl with the value in myDF2$pf_mcl. If a row does not match based on
?studyno?, the value should remain the same.
>
> It's probably worth mentioning, the two data frames have other
columns...I have selected a few for example purposes.
>
>
>
> ______________________________________________________________________
>
> This e-mail contains information which is confidential. It is intended only
for the use of the named recipient. If you have received this e-mail in error,
please let us know by replying to the sender, and immediately delete it from
your system.  Please note, that in these circumstances, the use, disclosure,
distribution or copying of this information is strictly prohibited.
KEMRI-Wellcome Trust Programme cannot accept any responsibility for the 
accuracy or completeness of this message as it has been transmitted over a
public network. Although the Programme has taken reasonable precautions to
ensure no viruses are present in emails, it cannot accept responsibility for any
loss or damage arising from the use of the email or attachments. Any views
expressed in this message are those of the individual sender, except where the
sender specifically states them to be the views of KEMRI-Wellcome Trust
Programme.
> ______________________________________________________________________
>
> 	[[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.
>

Dear @Bert Gunter<mailto:bgunter.4567 at gmail.com>, I tried merge and I
faced many challenges. @Rui Barradas<mailto:ruipbarradas at sapo.pt>
solution is working.

From: Bert Gunter <bgunter.4567 at gmail.com>
Date: Friday, 13 October 2017 at 22:44
To: Kevin Wamae <KWamae at kemri-wellcome.org>
Cc: R-help <R-help at r-project.org>
Subject: Re: [R] Populate one data frame with values from another dataframe for
rows that match

?merge

Bert

On Oct 13, 2017 12:09 PM, "Kevin Wamae" <KWamae at
kemri-wellcome.org<mailto:KWamae at kemri-wellcome.org>> wrote:
I'm trying to populate the column ?pf_mcl? in myDF1 with values from myDF2,
where rows match based on column "studyno" but the solutions I have
found so far don't seem to be giving me the desired output.

Below is a snapshot of the data.frames.

myDF1 <- structure(list(studyno = c("J1000/9", "J1000/9",
"J1000/9", "J1000/9",
"J1000/9", "J1000/9"), date = structure(c(17123, 17127,
17135,
17144, 17148, 17155), class = "Date"), pf_mcl = c(NA_integer_,
NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_
), year = c(2016, 2016, 2016, 2016, 2016, 2016)), .Names =
c("studyno",
"date", "pf_mcl", "year"), row.names = c(NA, 6L),
class = "data.frame")

myDF2 <- structure(list(studyno = c("J740/4", "J1000/9",
"J895/7", "J931/6",
"J609/1", "J941/3"), pf_mcl = c(0L, 0L, 0L, 0L, 0L, 0L)),
.Names = c("studyno",
"pf_mcl"), row.names = c(NA, 6L), class = "data.frame")

myDF2 is a well curated subset of myDF1. Some rows in the two datasets match
based on "studyno", one may find that values are missing in
myDF1$pf_mcl or the values are wrong.

All I want to do is identify a matching row in myDF2 and populate myDF1$pf_mcl
with the value in myDF2$pf_mcl. If a row does not match based on ?studyno?, the
value should remain the same.

It's probably worth mentioning, the two data frames have other columns...I
have selected a few for example purposes.



______________________________________________________________________

This e-mail contains information which is confidential. It is intended only for
the use of the named recipient. If you have received this e-mail in error,
please let us know by replying to the sender, and immediately delete it from
your system.  Please note, that in these circumstances, the use, disclosure,
distribution or copying of this information is strictly prohibited.
KEMRI-Wellcome Trust Programme cannot accept any responsibility for the 
accuracy or completeness of this message as it has been transmitted over a
public network. Although the Programme has taken reasonable precautions to
ensure no viruses are present in emails, it cannot accept responsibility for any
loss or damage arising from the use of the email or attachments. Any views
expressed in this message are those of the individual sender, except where the
sender specifically states them to be the views of KEMRI-Wellcome Trust
Programme.
______________________________________________________________________

        [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org<mailto: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.

______________________________________________________________________

This e-mail contains information which is confidential. It is intended only for
the use of the named recipient. If you have received this e-mail in error,
please let us know by replying to the sender, and immediately delete it from
your system.  Please note, that in these circumstances, the use, disclosure,
distribution or copying of this information is strictly prohibited.
KEMRI-Wellcome Trust Programme cannot accept any responsibility for the 
accuracy or completeness of this message as it has been transmitted over a
public network. Although the Programme has taken reasonable precautions to
ensure no viruses are present in emails, it cannot accept responsibility for any
loss or damage arising from the use of the email or attachments. Any views
expressed in this message are those of the individual sender, except where the
sender specifically states them to be the views of KEMRI-Wellcome Trust
Programme.
______________________________________________________________________

	[[alternative HTML version deleted]]

Dear @Rui Barradas, thank you for the solution. It works perfectly.


On 13/10/2017, 23:35, "Rui Barradas" <ruipbarradas at sapo.pt>
wrote:

    Hello,
    
    Try the following.
    
    
    myDF1$studyno <- as.character(myDF1$studyno)
    myDF2$studyno <- as.character(myDF2$studyno)
    i1 <- which(names(myDF1) == "pf_mcl")
    
    merge(myDF1[-i1], myDF2, by = "studyno")
    
    
    Hope this helps,
    
    Rui Barradas
    
    Em 13-10-2017 20:09, Kevin Wamae escreveu:
    > I'm trying to populate the column ?pf_mcl? in myDF1 with values
from myDF2, where rows match based on column "studyno" but the
solutions I have found so far don't seem to be giving me the desired output.
    >
    > Below is a snapshot of the data.frames.
    >
    > myDF1 <- structure(list(studyno = c("J1000/9",
"J1000/9", "J1000/9", "J1000/9",
    > "J1000/9", "J1000/9"), date = structure(c(17123,
17127, 17135,
    > 17144, 17148, 17155), class = "Date"), pf_mcl =
c(NA_integer_,
    > NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_
    > ), year = c(2016, 2016, 2016, 2016, 2016, 2016)), .Names =
c("studyno",
    > "date", "pf_mcl", "year"), row.names =
c(NA, 6L), class = "data.frame")
    >
    > myDF2 <- structure(list(studyno = c("J740/4",
"J1000/9", "J895/7", "J931/6",
    > "J609/1", "J941/3"), pf_mcl = c(0L, 0L, 0L, 0L, 0L,
0L)), .Names = c("studyno",
    > "pf_mcl"), row.names = c(NA, 6L), class =
"data.frame")
    >
    > myDF2 is a well curated subset of myDF1. Some rows in the two datasets
match based on "studyno", one may find that values are missing in
myDF1$pf_mcl or the values are wrong.
    >
    > All I want to do is identify a matching row in myDF2 and populate
myDF1$pf_mcl with the value in myDF2$pf_mcl. If a row does not match based on
?studyno?, the value should remain the same.
    >
    > It's probably worth mentioning, the two data frames have other
columns...I have selected a few for example purposes.
    >
    >
    >
    > ______________________________________________________________________
    >
    > This e-mail contains information which is confidential. It is intended
only for the use of the named recipient. If you have received this e-mail in
error, please let us know by replying to the sender, and immediately delete it
from your system.  Please note, that in these circumstances, the use,
disclosure, distribution or copying of this information is strictly prohibited.
KEMRI-Wellcome Trust Programme cannot accept any responsibility for the 
accuracy or completeness of this message as it has been transmitted over a
public network. Although the Programme has taken reasonable precautions to
ensure no viruses are present in emails, it cannot accept responsibility for any
loss or damage arising from the use of the email or attachments. Any views
expressed in this message are those of the individual sender, except where the
sender specifically states them to be the views of KEMRI-Wellcome Trust
Programme.
    > ______________________________________________________________________
    >
    > 	[[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.
    >
    


______________________________________________________________________

This e-mail contains information which is confidential. It is intended only for
the use of the named recipient. If you have received this e-mail in error,
please let us know by replying to the sender, and immediately delete it from
your system.  Please note, that in these circumstances, the use, disclosure,
distribution or copying of this information is strictly prohibited.
KEMRI-Wellcome Trust Programme cannot accept any responsibility for the 
accuracy or completeness of this message as it has been transmitted over a
public network. Although the Programme has taken reasonable precautions to
ensure no viruses are present in emails, it cannot accept responsibility for any
loss or damage arising from the use of the email or attachments. Any views
expressed in this message are those of the individual sender, except where the
sender specifically states them to be the views of KEMRI-Wellcome Trust
Programme.
______________________________________________________________________