> On Dec 5, 2016, at 7:29 AM, John Sorkin <jsor...@grecc.umaryland.edu> wrote:
>
> 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)
When you use that calling syntax, the system will supply the values of whatever
the `age` variable contains. (And if there is no `age`-named object, you get an
error at the time of the call to `myfun`. You need either to call it as:
myfun( mydf , "age")
# Or:
age <- "age"
myfun( mydf, age)
Unless your value of the `age`-named variable was "age" in the calling
environment (and you did not give us that value in either of your postings),
you would fail.
--
David.
>
>
>
>
> 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)
>>
>>
>>
>>
>>
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>
>
>
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