Hello,

For some reason I got moderation in reply to Bert's post so I'll retry.
Get rid of 'xx', keep 'yy':

frame[, yy]  # this works

Hope this helps,

Rui Barradas

Em 05-12-2016 15:29, John Sorkin escreveu:
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 <ruipbarra...@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:
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