How do I return the name of an argument in my function as a column value?

Question

I'm generating a reference table from a numerical vector and a vector of start dates. I want one of the columns in my reference table to equal the name of my first argument (it should read "Ekonom" for each row). This is important since I will join several tables together and since I need to tell my observations apart.

My input:

Ekonom<-c(15,15,15,15,7.5,7.5,15,7.5,7.5,15,15,15,30,0)
sdEkonom<-structure(c(15586, 15950, 16314, 16678, 17042, 17406, 17777, 
18141), class = "Date")

My program is as follows:

reference_table<-function(x,y){
summer_break<-ifelse(cumsum(x)<=60, 0, ifelse(cumsum(x)>60 & cumsum(x)<=120 , 1,2))
program<-cbind(x,summer_break)
program<-as.data.frame(program)
program<-program%>%rename(points=x)
program<-program%>%mutate(program=as.character(rlang::enexpr(x)))
program<-program%>%mutate(weeks_course=points/1.5)
program<-program%>%mutate(points_expected=lag(cumsum(points)))
program<-program%>%mutate(points_expected=ifelse(is.na(points_expected),0,points_expected))
program<-program%>%mutate(order=1:n())
program<-crossing(y, program)
program<-program%>%arrange(y, order)
program<-program%>%mutate(starttermin=ifelse(order==1,1,0))
program$kull<-cumsum(program$starttermin)
program<-program%>%mutate(start_date=y-1)
program<-program%>%group_by(kull)%>%mutate(start_date_points=start_date+lag(cumsum(weeks_course)*7+3*7+summer_break*12*7))
program<-program%>%group_by(kull)%>%mutate(end_date_points=start_date+cumsum(weeks_course)*7+3*7+summer_break*12*7-1)
program<-program%>%mutate(start_date_points=if_else(is.na(start_date_points),start_date,as.Date(start_date_points)))
program<-program%>%group_by(start_date)%>%mutate(finished_date=max(start_date_points))
program<-program%>%mutate(finished=ifelse(lead(kull, default=0)==kull,0,1))
}

What's particularly importamt is this row:

program<-program%>%mutate(program=as.character(rlang::enexpr(x)))

I execute the program by writing:

ekon_program<-reference_table(Ekonom, sdEkonom)

For some reason the function has not evaluated x as "Ekonom" but as "15" in my program column. Why is this happening and how do I get the correct output?

score 1 · Accepted Answer · answered Jan 15 '20 at 08:39

Define the variable earlier and use it later in the function

library(dplyr)

reference_table<-function(x,y){

   col_values <- as.character(rlang::enexpr(x))
   summer_break<- ifelse(cumsum(x)<=60, 0, 
                         ifelse(cumsum(x) > 60 & cumsum(x)<=120 , 1,2))
   program<- data.frame(x,summer_break)
   program %>%
      rename(points=x) %>%
      mutate(program = col_values) 
}

reference_table(Ekonom, sdEkonom)

#   points summer_break program
#1    15.0            0  Ekonom
#2    15.0            0  Ekonom
#3    15.0            0  Ekonom
#4    15.0            0  Ekonom
#5     7.5            1  Ekonom
#6     7.5            1  Ekonom
#7    15.0            1  Ekonom
#8     7.5            1  Ekonom
#9     7.5            1  Ekonom
#10   15.0            1  Ekonom
#11   15.0            2  Ekonom
#12   15.0            2  Ekonom
#13   30.0            2  Ekonom
#14    0.0            2  Ekonom

In this case, you can also use

col_values <- deparse(substitute(x))

How do I return the name of an argument in my function as a column value?

1 Answers1