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John Sorkin

2015-Dec-02 02:45 UTC

[R] Function calling a function, column name not passed properly

David has  told me that my problem is because there is not column varscr
in my dataframe. I know this. My question is how can I modify my code so
that the second call to SmallFn will in fact access the column Wstscr
which does, in fact exist in the dataframe.
John

Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] 
> On Dec 1, 2015, at 2:57 PM, John Sorkin <jsorkin atgrecc.umaryland.edu> wrote:> > I am trying to write a function that
calls a function. The first call to SmallFn works without any problem,
printing both the passed data and the column Wstscr. The second call
does not work (error, Error in d[, column] : subscript out of bounds).
>> The first call shows what I am trying to do with the second call. I ampassing to the outer function doit12 the beginning of the name of the
column that I want to access (Wst). doit12 creates the full name of the
column (Wstscr) by using varxx <- deparse(susbstitute(variable)) and
varscr <- paste(varxx,"scr",sep=""). I can access the
column in doit12
as seen by the results of   print(data[,varscr]).> > SmallFn works when
it is called using SmallFn(Wstscr,data), but fails when called with
SmallFn(varscr,data). I don't understand why the second call fails.
varscr was shown to represent Wstscr.> > Please tell my why the second
call is not working, please put me out of one-full day of misery!It?s
telling you there is no column in that dataframe with the name ?varscr?.?
David.

I am trying to write a function that calls a function. The first call to
SmallFn works without any problem, printing both the passed data and the
column Wstscr. The second call does not work (error, Error in d[,
column] : subscript out of bounds). 

The first call shows what I am trying to do with the second call. I am
passing to the outer function doit12 the beginning of the name of the
column that I want to access (Wst). doit12 creates the full name of the
column (Wstscr) by using varxx <- deparse(susbstitute(variable)) and
varscr <- paste(varxx,"scr",sep=""). I can access the
column in doit12
as seen by the results of   print(data[,varscr]).

SmallFn works when it is called using SmallFn(Wstscr,data), but fails
when called with SmallFn(varscr,data). I don't understand why the second
call fails. varscr was shown to represent Wstscr.

Please tell my why the second call is not working, please put me out of
one-full day of misery!

Thank you,
John

mydata <- cbind(  
patient_id=c(10163,10987,19882,19899,20104,20105,20167,20318,20338,20392),

Wstscr=c(139.00,NA,101.80,103.00,76.40,116.00,139.80,111.31,NA,150.00)) 

mydata     

doit12 <-function(variable,data) {

  varxx <- deparse(substitute(variable))
  cat("varxx created from first deparse
substitute=",varxx,"\n")
  varscr <- paste(varxx,"scr",sep="")
  cat("1varscr=",varscr,"\n")
  cat("Data inside doit12\n")
  print(data)
  cat("Print the Wstscr column of data. varscr created using paste after
deparse substitute\n")
  print(data[,varscr])
  cat("\n\n")

  SmallFn <- function(v,d) {
    cat("\nInside SmallFn\n")
    zz <-match.call()
    column <- deparse(substitute(v))
    cat("column=",column,"\n")
    cat("The results of match.call\n")
    print(zz)
    print("Hello world!")
    print(d)
    print(d[,column])
  }
  SmallFn(Wstscr,data)
  SmallFn(varscr,data)
}
doit12(Wst,mydata)

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) 410-605-7119410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing) 

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John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of MedicineBaltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing) 

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William Dunlap

2015-Dec-02 03:17 UTC

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[R] Function calling a function, column name not passed properly

The short answer is to provide an argument that your function does not
pass through substitute(), so standard evaluation takes place.  E.g., change
    SmallFn <- function(v,d) {
        column <- deparse(substitute(v))
        d[,column]
    }
to
    SmallFn <- function(v, d, column=deparse(substitute(v))) {
        d[,column]
    }
and call it as either
    SmallFn(firstColumn, d=data.frame(firstColumn=1:3))
or
    col <- "firstColumn"
    SmallFn(column=col, d=data.frame(firstColumn=1:3))

If you want to get fancy, check out Hadley's lazyeval package.

Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Tue, Dec 1, 2015 at 6:45 PM, John Sorkin <jsorkin at
grecc.umaryland.edu> wrote:> David has  told me that my problem is because there is not column varscr
> in my dataframe. I know this. My question is how can I modify my code so
> that the second call to SmallFn will in fact access the column Wstscr
> which does, in fact exist in the dataframe.
> John
>
> Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
>
>> On Dec 1, 2015, at 2:57 PM, John Sorkin <jsorkin at
> grecc.umaryland.edu> wrote:> > I am trying to write a function
that
> calls a function. The first call to SmallFn works without any problem,
> printing both the passed data and the column Wstscr. The second call
> does not work (error, Error in d[, column] : subscript out of bounds). >
>> The first call shows what I am trying to do with the second call. I am
> passing to the outer function doit12 the beginning of the name of the
> column that I want to access (Wst). doit12 creates the full name of the
> column (Wstscr) by using varxx <- deparse(susbstitute(variable)) and
> varscr <- paste(varxx,"scr",sep=""). I can access
the column in doit12
> as seen by the results of   print(data[,varscr]).> > SmallFn works
when
> it is called using SmallFn(Wstscr,data), but fails when called with
> SmallFn(varscr,data). I don't understand why the second call fails.
> varscr was shown to represent Wstscr.> > Please tell my why the
second
> call is not working, please put me out of one-full day of misery!It?s
> telling you there is no column in that dataframe with the name ?varscr?.?
> David.
>
>
>
>
> I am trying to write a function that calls a function. The first call to
> SmallFn works without any problem, printing both the passed data and the
> column Wstscr. The second call does not work (error, Error in d[,
> column] : subscript out of bounds).
>
> The first call shows what I am trying to do with the second call. I am
> passing to the outer function doit12 the beginning of the name of the
> column that I want to access (Wst). doit12 creates the full name of the
> column (Wstscr) by using varxx <- deparse(susbstitute(variable)) and
> varscr <- paste(varxx,"scr",sep=""). I can access
the column in doit12
> as seen by the results of   print(data[,varscr]).
>
> SmallFn works when it is called using SmallFn(Wstscr,data), but fails
> when called with SmallFn(varscr,data). I don't understand why the
second
> call fails. varscr was shown to represent Wstscr.
>
> Please tell my why the second call is not working, please put me out of
> one-full day of misery!
>
> Thank you,
> John
>
>
>
>
> mydata <- cbind(
> patient_id=c(10163,10987,19882,19899,20104,20105,20167,20318,20338,20392),
>
> Wstscr=c(139.00,NA,101.80,103.00,76.40,116.00,139.80,111.31,NA,150.00))
>
> mydata
>
> doit12 <-function(variable,data) {
>
>   varxx <- deparse(substitute(variable))
>   cat("varxx created from first deparse
substitute=",varxx,"\n")
>   varscr <- paste(varxx,"scr",sep="")
>   cat("1varscr=",varscr,"\n")
>   cat("Data inside doit12\n")
>   print(data)
>   cat("Print the Wstscr column of data. varscr created using paste
after
> deparse substitute\n")
>   print(data[,varscr])
>   cat("\n\n")
>
>   SmallFn <- function(v,d) {
>     cat("\nInside SmallFn\n")
>     zz <-match.call()
>     column <- deparse(substitute(v))
>     cat("column=",column,"\n")
>     cat("The results of match.call\n")
>     print(zz)
>     print("Hello world!")
>     print(d)
>     print(d[,column])
>   }
>   SmallFn(Wstscr,data)
>   SmallFn(varscr,data)
> }
> doit12(Wst,mydata)
>
>
>
> 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) 410-605-7119410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>
>
>
>
>
> Call
>
> Call from mobile
>
> Send SMS
>
> Add to Skype
>
> You'll need Skype CreditFree via Skype
> John David Sorkin M.D., Ph.D.
> Professor of Medicine
> Chief, Biostatistics and Informatics
> University of Maryland School of MedicineBaltimore, 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:12}}

R help - Dec 2015 - Function calling a function, column name not passed properly

[R] Function calling a function, column name not passed properly

[R] Function calling a function, column name not passed properly