Thanks to several kind people, I understand how to use
deparse(substitute(paramter)) to get as text strings the arguments passed to an
R function. What I still can't do is put the text strings recovered by
deparse(substitute(parameter)) back together to get the columns of a dataframe
passed to the function. What I want to do is pass a column name to a function
along with the name of the dataframe and then, within the function access the
column of the dataframe.
I want the function below to print the columns of the dataframe testdata, i.e.
testdata[,"FSG"] and testdata[,"GCM"]. I have tried several
ways to tell the function to print the columns; none of them work.
I thank everyone who has helped in the past, and those people who will help me
now!
John
testdata <- structure(list(FSG = c(271L, 288L, 269L, 297L, 311L, 217L, 235L,
172L, 201L, 162L), CGM = c(205L, 273L, 226L,
235L, 311L, 201L,
203L, 155L, 182L, 163L)), row.names = c(NA,
10L), class = "data.frame")
cat("This is the data frame")
class(testdata)
testdata
BAPlot <- function(first,second,indata){
# these lines of code work
col1 <- deparse(substitute(first))
col2 <- deparse(substitute(second))
thedata <- deparse(substitute(third))
print(col1)
print(col2)
print(thedata)
cat("This gets the data, but not as a dataframe\n")
zoop<-paste(indata)
print(zoop)
cat("End This gets the data, but not as a dataframe\n")
# these lines do not work
print(indata[,first])
print(indata[,"first"])
print(thedata[,col1])
paste(zoop[,paste(first)])
paste(zoop[,first])
zap<-paste(first)
print(zap)
}
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Basically, huh?> df <- data.frame(a = 1:3, b = letters[1:3]) > nm <- names(df) > print(df[,nm[1]])[1] 1 2 3> print(df[,nm[2]])[1] a b c Levels: a b c This can be done within a function, of course:> demo <- function(df, colnames){+ print(df[,colnames]) + }> demo(df,c("a","b"))a b 1 1 a 2 2 b 3 3 c Am I missing something? (Apologies, if so). Bert Gunter On Wed, May 29, 2019 at 6:40 PM Sorkin, John <jsorkin at som.umaryland.edu> wrote:> Thanks to several kind people, I understand how to use > deparse(substitute(paramter)) to get as text strings the arguments passed > to an R function. What I still can't do is put the text strings recovered > by deparse(substitute(parameter)) back together to get the columns of a > dataframe passed to the function. What I want to do is pass a column name > to a function along with the name of the dataframe and then, within the > function access the column of the dataframe. > > I want the function below to print the columns of the dataframe testdata, > i.e. testdata[,"FSG"] and testdata[,"GCM"]. I have tried several ways to > tell the function to print the columns; none of them work. > > I thank everyone who has helped in the past, and those people who will > help me now! > > John > > testdata <- structure(list(FSG = c(271L, 288L, 269L, 297L, 311L, 217L, > 235L, > > 172L, 201L, 162L), CGM = c(205L, 273L, > 226L, 235L, 311L, 201L, > > 203L, 155L, 182L, 163L)), row.names > c(NA, 10L), class = "data.frame") > > cat("This is the data frame") > > class(testdata) > > testdata > > > > BAPlot <- function(first,second,indata){ > > # these lines of code work > > col1 <- deparse(substitute(first)) > > col2 <- deparse(substitute(second)) > > thedata <- deparse(substitute(third)) > > print(col1) > > print(col2) > > print(thedata) > > cat("This gets the data, but not as a dataframe\n") > > zoop<-paste(indata) > > print(zoop) > > cat("End This gets the data, but not as a dataframe\n") > > # these lines do not work > > print(indata[,first]) > > print(indata[,"first"]) > > print(thedata[,col1]) > > paste(zoop[,paste(first)]) > > paste(zoop[,first]) > > zap<-paste(first) > > print(zap) > > } > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. >[[alternative HTML version deleted]]
Bert, Thank you for your reply. You are correct that your code will print the contents of the data frame. While it works, it is not as elegant as the lm function. One does not have to pass the independent and dependent variables to lm In parentheses. Fit1<-lm(y~x,data=mydata) None of the parameters to lm are passed in quotation marks. Somehow, using deparse(substitute()) and other magic lm is able to get the data in the dataframe mydata. I want to be able to do the same magic in functions I write; pass a dataframe and column names, all without quotation marks and be able to write code that will provide access to the columns of the dataframe without having to pass the column names in quotation marks. Thank you, John 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<x-apple-data-detectors://12> GRECC<x-apple-data-detectors://12> (BT/18/GR) Baltimore, MD 21201-1524<x-apple-data-detectors://13/0> (Phone) 410-605-711<tel:410-605-7119>9 (Fax) 410-605-7913<tel:410-605-7913> (Please call phone number above prior to faxing) On May 29, 2019, at 9:59 PM, Bert Gunter <bgunter.4567 at gmail.com<mailto:bgunter.4567 at gmail.com>> wrote: Basically, huh?> df <- data.frame(a = 1:3, b = letters[1:3]) > nm <- names(df) > print(df[,nm[1]])[1] 1 2 3> print(df[,nm[2]])[1] a b c Levels: a b c This can be done within a function, of course:> demo <- function(df, colnames){+ print(df[,colnames]) + }> demo(df,c("a","b"))a b 1 1 a 2 2 b 3 3 c Am I missing something? (Apologies, if so). Bert Gunter On Wed, May 29, 2019 at 6:40 PM Sorkin, John <jsorkin at som.umaryland.edu<mailto:jsorkin at som.umaryland.edu>> wrote: Thanks to several kind people, I understand how to use deparse(substitute(paramter)) to get as text strings the arguments passed to an R function. What I still can't do is put the text strings recovered by deparse(substitute(parameter)) back together to get the columns of a dataframe passed to the function. What I want to do is pass a column name to a function along with the name of the dataframe and then, within the function access the column of the dataframe. I want the function below to print the columns of the dataframe testdata, i.e. testdata[,"FSG"] and testdata[,"GCM"]. I have tried several ways to tell the function to print the columns; none of them work. I thank everyone who has helped in the past, and those people who will help me now! John testdata <- structure(list(FSG = c(271L, 288L, 269L, 297L, 311L, 217L, 235L, 172L, 201L, 162L), CGM = c(205L, 273L, 226L, 235L, 311L, 201L, 203L, 155L, 182L, 163L)), row.names = c(NA, 10L), class = "data.frame") cat("This is the data frame") class(testdata) testdata BAPlot <- function(first,second,indata){ # these lines of code work col1 <- deparse(substitute(first)) col2 <- deparse(substitute(second)) thedata <- deparse(substitute(third)) print(col1) print(col2) print(thedata) cat("This gets the data, but not as a dataframe\n") zoop<-paste(indata) print(zoop) cat("End This gets the data, but not as a dataframe\n") # these lines do not work print(indata[,first]) print(indata[,"first"]) print(thedata[,col1]) paste(zoop[,paste(first)]) paste(zoop[,first]) zap<-paste(first) print(zap) } [[alternative HTML version deleted]] ______________________________________________ R-help at r-project.org<mailto: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. [[alternative HTML version deleted]]