How to use different column names in a function in R

Question

My data are similar to the following data:

df<-read.table(text=" degree
100
120
140
150
160",header=TRUE)

and I have this simple function

df1<-function(x){
mean(df$degree)
}
df1(df)

I get the mean. However, sometimes I want to use different names for the column name, say 'point' instead of the 'degree'. Indeed, I do not want to use 'degree' in my codes. Happy to describe should you think it is necessary.

Answer 1

We can pass an argument for column name

f1 <- function(dat, colNm) mean(dat[[colNm]], na.rm = TRUE)
f1(df, "degree")
#[1] 134

f1(setNames(df, "point"), "point")
#[1] 134