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

[Rui Barradas]

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}}
>
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