Adjust a function's argument in R-CodePudding

How do I put all XMR arguments from below dataset as argument inside a function at once?

I could do like this:

f1 <- function(X1,X2,X3,X4, XM1, XMR0, XMR01, XMR02, XMR03, XMR4){
  
  x2<-df1 %>% select(starts_with("XMR"))
  x2<-cbind(df1, setNames(df1$XM1 - x2, paste0(names(x2), "_PA")))
  x3<-select(x2,X1,X2,X3,X4,XM1,ends_with("PA"))

return(x3)
 }

However, if I had a lot of XMR, it would be bad to put several XMR. Is there any easier way to do it?

  df1 <- structure(
  list(
    X1 = c(1, 1, 1, 1),
    X2 = c("4","3","1","2"),
    X3 = c("1", "2","3","2"),
    X4 = c("1", "2","3","2"),
    XM1 = c(200, 300, 200, 200),
    XMR0 = c(300, 300, 300, 300),
    XMR01 = c(300, 300, 300, 300),
    XMR02 = c(300,300,300,300),
    XMR03 = c(300,300,300,300),
    XMR04 = c(300,250,350,350)),row.names = c(NA, 4L), class = "data.frame")

CodePudding user response：

It would be easier with do.call (assuming the arguments to the functions are in the same order as the columns of the data)

do.call(f1, as.list(colnames(df1)))
 X1 X2 X3 XM1 XMR0_PA XMR01_PA XMR02_PA XMR03_PA XMR04_PA
1  1  4  1 200    -100     -100     -100     -100     -100
2  1  3  2 300       0        0        0        0       50
3  1  1  3 200    -100     -100     -100     -100     -150
4  1  2  2 200    -100     -100     -100     -100     -150

The function can be also written as

f2 <- function(data){ 
  
  data %>% 
     transmute(across(matches("^X\\d $")),
      XM1, across(starts_with("XMR"), ~ XM1 - .x, 
        .names = "{.col}_PA" )) 
  }

and then we use as

> f2(df1)
  X1 X2 X3 XM1 XMR0_PA XMR01_PA XMR02_PA XMR03_PA XMR04_PA
1  1  4  1 200    -100     -100     -100     -100     -100
2  1  3  2 300       0        0        0        0       50
3  1  1  3 200    -100     -100     -100     -100     -150
4  1  2  2 200    -100     -100     -100     -100     -150