R- pass argument to ggplot in function

问题

I have a question about how to pass an argument to ggplot if I want to have a 1-x x-axis. The function is being used to specify column name in my data frame.

Let's say my data frame looks like

x1    x2    x3   x4
0.1   0.2   0.3  0.4
0.3   0.5   0.7  0.9
0.4   0.6   0.8  0.2

And I have a function

myfunction<- function(x, y, convert = False){

if (flip) {
  ggplot(data = mydata, aes(x=1-get(x), y=get(y))) + geom_line() + 
  xlab(x) + ylab(y)
    } else {
  ggplot(data = mydata, aes(x=get(x), y=get(y))) + geom_line() + 
  xlab(x) + ylab(y)
    }
}

It works when convert = False, but if I want to plot myfunction(x1, x2, convert = TRUE), my x-lab is still "x1", not "1-x1". I have tried to code xlab(1-get(x)) but it doesn't work. Anyone have an idea about how to print x-label as "1-x1", where x1 is a column name in a data frame?

回答1:

Based on the function arguments, it seems like convert is flip. Instead of using get to modify the 'x' argument, we can do this with mutate after converting the arguments to quosures

myfunction<- function(mydata, x, y, convert = FALSE){
    x <- enquo(x)
    y <- enquo(y)
    xnew <- quo_name(x)
if (convert) {
   mydata %>%
         mutate(!! (xnew) := 1- !!(x)) %>%
         ggplot(., aes_string(xnew, quo_name(y))) +
               geom_line() + 
               xlab(paste0("1 - ", xnew))
   
} else {

     ggplot(mydata, aes_string(xnew, quo_name(y))) +
             geom_line()

    }
    
}

myfunction(df1, x1, x2, convert = TRUE)

-output

myfunction(df1, x1, x2, convert = FALSE)

-output

data

df1 <- structure(list(x1 = c(0.1, 0.3, 0.4), x2 = c(0.2, 0.5, 0.6), 
x3 = c(0.3, 0.7, 0.8), x4 = c(0.4, 0.9, 0.2)), .Names = c("x1", 
"x2", "x3", "x4"), class = "data.frame", row.names = c(NA, -3L
))

来源：https://stackoverflow.com/questions/48982011/r-pass-argument-to-ggplot-in-function

标签

function

ggplot2

arguments