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John Sorkin

2016-Dec-05 14:44 UTC

[R] Write a function that allows access to columns of a passed dataframe.

I am trying to write a function which, when passed the name of a dataframe and
the name of a column of the dataframe, will allow me to work on the columns of a
dataframe. I can not get my code to work. Please see the code below. Any help in
getting the function to work would be appreciated.




mydf <-
data.frame(id=c(1,2,3,4,5),sex=c("M","M","M","F","F"),age=c(20,34,43,32,21))
mydf
class(mydf)


myfun <- function(frame,var){
  call <- match.call()
  print(call)


  indx <- match(c("frame","var"),names(call),nomatch=0)
  print(indx)
  if(indx[1]==0) stop("Function called without sufficient arguments!")


  cat("I can get the name of the dataframe as a text string!\n")
  xx <- deparse(substitute(frame))
  print(xx)


  cat("I can get the name of the column as a text string!\n")
  yy <- deparse(substitute(var))
  print(yy)


  # This does not work.
  col <- xx[,"yy"]


  # Nor does this work.
  col <- xx[,yy]
  print(col)
}


myfun(mydf,age)

John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric
Medicine
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing) 




John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric
Medicine
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing) 





Confidentiality Statement:
This email message, including any attachments, is for the sole use of the
intended recipient(s) and may contain confidential and privileged information.
Any unauthorized use, disclosure or distribution is prohibited. If you are not
the intended recipient, please contact the sender by reply email and destroy all
copies of the original message.

Rui Barradas

2016-Dec-05 15:17 UTC

head link

[R] Write a function that allows access to columns of a passed dataframe.

Hello,

You don't need xx <- deparse(substitute(...)), since you are passing the 
data.frame to your function. Just use


myfun <- function(frame,var){

   [...]

   # Nor does this work.
   col <- frame[,yy]
   print(col)
}

myfun(mydf,age)
myfun(frame = mydf, var = age)
[1] 2 3
I can get the name of the dataframe as a text string!
[1] "mydf"
I can get the name of the column as a text string!
[1] "age"
[1] 20 34 43 32 21


Hope this helps,

Rui Barradas



Em 05-12-2016 14:44, John Sorkin escreveu:> I am trying to write a function which, when passed the name of a dataframe
and the name of a column of the dataframe, will allow me to work on the columns
of a dataframe. I can not get my code to work. Please see the code below. Any
help in getting the function to work would be appreciated.
>
>
>
>
> mydf <-
data.frame(id=c(1,2,3,4,5),sex=c("M","M","M","F","F"),age=c(20,34,43,32,21))
> mydf
> class(mydf)
>
>
> myfun <- function(frame,var){
>    call <- match.call()
>    print(call)
>
>
>    indx <-
match(c("frame","var"),names(call),nomatch=0)
>    print(indx)
>    if(indx[1]==0) stop("Function called without sufficient
arguments!")
>
>
>    cat("I can get the name of the dataframe as a text string!\n")
>    xx <- deparse(substitute(frame))
>    print(xx)
>
>
>    cat("I can get the name of the column as a text string!\n")
>    yy <- deparse(substitute(var))
>    print(yy)
>
>
>    # This does not work.
>    col <- xx[,"yy"]
>
>
>    # Nor does this work.
>    col <- xx[,yy]
>    print(col)
> }
>
>
> myfun(mydf,age)
>
> John David Sorkin M.D., Ph.D.
> Professor of Medicine
> Chief, Biostatistics and Informatics
> University of Maryland School of Medicine Division of Gerontology and
Geriatric Medicine
> Baltimore VA Medical Center
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> (Phone) 410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>
>
>
>
> John David Sorkin M.D., Ph.D.
> Professor of Medicine
> Chief, Biostatistics and Informatics
> University of Maryland School of Medicine Division of Gerontology and
Geriatric Medicine
> Baltimore VA Medical Center
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> (Phone) 410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>
>
>
>
>
> Confidentiality Statement:
> This email message, including any attachments, is for ...{{dropped:8}}

Rui Barradas

2016-Dec-05 15:23 UTC

head link

[R] Write a function that allows access to columns of a passed dataframe.

I forgot to say that I've commented out the line

# This does not work.
#col <- xx[,"yy"]

Rui Barradas

Em 05-12-2016 15:17, Rui Barradas escreveu:> Hello,
>
> You don't need xx <- deparse(substitute(...)), since you are passing
the
> data.frame to your function. Just use
>
>
> myfun <- function(frame,var){
>
>    [...]
>
>    # Nor does this work.
>    col <- frame[,yy]
>    print(col)
> }
>
> myfun(mydf,age)
> myfun(frame = mydf, var = age)
> [1] 2 3
> I can get the name of the dataframe as a text string!
> [1] "mydf"
> I can get the name of the column as a text string!
> [1] "age"
> [1] 20 34 43 32 21
>
>
> Hope this helps,
>
> Rui Barradas
>
>
>
> Em 05-12-2016 14:44, John Sorkin escreveu:
>> I am trying to write a function which, when passed the name of a
>> dataframe and the name of a column of the dataframe, will allow me to
>> work on the columns of a dataframe. I can not get my code to work.
>> Please see the code below. Any help in getting the function to work
>> would be appreciated.
>>
>>
>>
>>
>> mydf <-
>>
data.frame(id=c(1,2,3,4,5),sex=c("M","M","M","F","F"),age=c(20,34,43,32,21))
>>
>> mydf
>> class(mydf)
>>
>>
>> myfun <- function(frame,var){
>>    call <- match.call()
>>    print(call)
>>
>>
>>    indx <-
match(c("frame","var"),names(call),nomatch=0)
>>    print(indx)
>>    if(indx[1]==0) stop("Function called without sufficient
arguments!")
>>
>>
>>    cat("I can get the name of the dataframe as a text
string!\n")
>>    xx <- deparse(substitute(frame))
>>    print(xx)
>>
>>
>>    cat("I can get the name of the column as a text
string!\n")
>>    yy <- deparse(substitute(var))
>>    print(yy)
>>
>>
>>    # This does not work.
>>    col <- xx[,"yy"]
>>
>>
>>    # Nor does this work.
>>    col <- xx[,yy]
>>    print(col)
>> }
>>
>>
>> myfun(mydf,age)
>>
>> John David Sorkin M.D., Ph.D.
>> Professor of Medicine
>> Chief, Biostatistics and Informatics
>> University of Maryland School of Medicine Division of Gerontology and
>> Geriatric Medicine
>> Baltimore VA Medical Center
>> 10 North Greene Street
>> GRECC (BT/18/GR)
>> Baltimore, MD 21201-1524
>> (Phone) 410-605-7119
>> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>>
>>
>>
>>
>> John David Sorkin M.D., Ph.D.
>> Professor of Medicine
>> Chief, Biostatistics and Informatics
>> University of Maryland School of Medicine Division of Gerontology and
>> Geriatric Medicine
>> Baltimore VA Medical Center
>> 10 North Greene Street
>> GRECC (BT/18/GR)
>> Baltimore, MD 21201-1524
>> (Phone) 410-605-7119
>> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>>
>>
>>
>>
>>
>> Confidentiality Statement:
>> This email message, including any attachments, is for ...{{dropped:8}}
>
> ______________________________________________
> 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.

John Sorkin

2016-Dec-05 15:29 UTC

head link

[R] Write a function that allows access to columns of a passed dataframe.

Rui,
I appreciate your suggestion, but eliminating the deparse statement does not
solve my problem. Do you have any other suggestions? See code below.
Thank you,
John


mydf <-
data.frame(id=c(1,2,3,4,5),sex=c("M","M","M","F","F"),age=c(20,34,43,32,21))
mydf
class(mydf)


myfun <- function(frame,var){
  call <- match.call()
  print(call)


  indx <- match(c("frame","var"),names(call),nomatch=0)
  print(indx)
  if(indx[1]==0) stop("Function called without sufficient arguments!")


  cat("I can get the name of the dataframe as a text string!\n")
  #xx <- deparse(substitute(frame))
  print(xx)


  cat("I can get the name of the column as a text string!\n")
  #yy <- deparse(substitute(var))
  print(yy)


  # This does not work.
  print(frame[,var])


  # This does not work.
  print(frame[,"var"])




  # This does not work.
  col <- xx[,"yy"]


  # Nor does this work.
  col <- xx[,yy]
  print(col)
}


myfun(mydf,age)




myfun()














John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric
Medicine
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing) 
>>> Rui Barradas <ruipbarradas at sapo.pt> 12/05/16 10:17 AM
>>>Hello,

You don't need xx <- deparse(substitute(...)), since you are passing the 
data.frame to your function. Just use


myfun <- function(frame,var){

   [...]

   # Nor does this work.
   col <- frame[,yy]
   print(col)
}

myfun(mydf,age)
myfun(frame = mydf, var = age)
[1] 2 3
I can get the name of the dataframe as a text string!
[1] "mydf"
I can get the name of the column as a text string!
[1] "age"
[1] 20 34 43 32 21


Hope this helps,

Rui Barradas



Em 05-12-2016 14:44, John Sorkin escreveu:> I am trying to write a function which, when passed the name of a dataframe
and the name of a column of the dataframe, will allow me to work on the columns
of a dataframe. I can not get my code to work. Please see the code below. Any
help in getting the function to work would be appreciated.
>
>
>
>
> mydf <-
data.frame(id=c(1,2,3,4,5),sex=c("M","M","M","F","F"),age=c(20,34,43,32,21))
> mydf
> class(mydf)
>
>
> myfun <- function(frame,var){
>    call <- match.call()
>    print(call)
>
>
>    indx <-
match(c("frame","var"),names(call),nomatch=0)
>    print(indx)
>    if(indx[1]==0) stop("Function called without sufficient
arguments!")
>
>
>    cat("I can get the name of the dataframe as a text string!\n")
>    xx <- deparse(substitute(frame))
>    print(xx)
>
>
>    cat("I can get the name of the column as a text string!\n")
>    yy <- deparse(substitute(var))
>    print(yy)
>
>
>    # This does not work.
>    col <- xx[,"yy"]
>
>
>    # Nor does this work.
>    col <- xx[,yy]
>    print(col)
> }
>
>
> myfun(mydf,age)
>
> John David Sorkin M.D., Ph.D.
> Professor of Medicine
> Chief, Biostatistics and Informatics
> University of Maryland School of Medicine Division of Gerontology and
Geriatric Medicine
> Baltimore VA Medical Center
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> (Phone) 410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>
>
>
>
> John David Sorkin M.D., Ph.D.
> Professor of Medicine
> Chief, Biostatistics and Informatics
> University of Maryland School of Medicine Division of Gerontology and
Geriatric Medicine
> Baltimore VA Medical Center
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> (Phone) 410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>
>
>
>
>
> Confidentiality Statement:
> This email message, including any attachments, is for the sole use of the
intended recipient(s) and may contain confidential and privileged information.
Any unauthorized use, disclosure or distribution is prohibited. If you are not
the intended recipient, please contact the sender by reply email and destroy all
copies of the original message.
> ______________________________________________
> 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.
>


Confidentiality Statement:
This email message, including any attachments, is for the sole use of the
intended recipient(s) and may contain confidential and privileged information.
Any unauthorized use, disclosure or distribution is prohibited. If you are not
the intended recipient, please contact the sender by reply email and destroy all
copies of the original message.

R help - Dec 2016 - Write a function that allows access to columns of a passed dataframe.

[R] Write a function that allows access to columns of a passed dataframe.

[R] Write a function that allows access to columns of a passed dataframe.

[R] Write a function that allows access to columns of a passed dataframe.

[R] Write a function that allows access to columns of a passed dataframe.