Generate a function based upon name data in a csv file opened in R -

i have dataframe of variable names , weightings.

example:

names <- c("a","b","c") weightings <- c(1,2,3) df <- cbind(names,weightings) 

i need generate function data such.

myfun <- function(x,data){ data[x,"a"]*1+data[x,"b"]*2+data[x,"c"]*3} 

i have dataframe named data column names match a, b, , c , apply myfun data on rows.

the issue have size of names , weightings vector can vary. working 5 names , weightings want generate new function "myfun" such.

newnames <- c("a","b","c","d","e") newweightings <- c(1,2,3,4,5)  myfun <- function(data){ data[x,"a"]*1+data[x,"b"]*2+data[x,"c"]*3+data[x,"d"]*4+data[x,"e"]*5} 

is there easy way automate creation of function give code, , .csv file of column names , weightings , generate new function.

what strategy this. use function make function

getmyfunction <- function(columns, weights)  {     stopifnot(length(columns)==length(weights))     function(x, data) {         rowsums(data[x, columns] * weights)     } } 

basically rowsums takes care of addition, specify vector of columns @ once, , default * element-wise takes care of weights.

then build function like

names <- c("a","b","c") weightings <- c(1,2,3) myfun <- getmyfunction(names, weightings) 

and can use with

dd<-data.frame(a=c(1,1), b=c(1,2), c=c(1,3))  myfun(1,dd) # [1] 6 myfun(2,dd) # [1] 13 myfun(1:2,dd) # [1] 6 13