r - Refering to a variable of the data frame passed in the 'data' parameter of ggplot function -

i use variable of dataframe passed data parameter of function ggplot in ggplot2 function in same call.

for instance, in following example want refer variable x in dataframe passed data parameter in ggplot in function scale_x_continuous such in:

library(ggplot2)  set.seed(2017)  samp <- sample(x = 20, size= 1000, replace = t)  ggplot(data = data.frame(x = samp), mapping = aes(x = x)) + geom_bar() + scale_x_continuous(breaks = seq(min(x), max(x))) 

and error :

error in seq(min(x)) : object 'x' not found 

which understand. of course can avoid problem doing :

df <- data.frame(x = samp) ggplot(data = df, mapping = aes(x = x)) + geom_bar() + scale_x_continuous(breaks = seq(min(df$x), max(df$x))) 

but don't want forced define object df outside call ggplot. want able directly refer variables in dataframe passed in data.

thanks lot

you write helper function initilialize plot

helper <- function(df, col) {      ggplot(data = df, mapping = aes_string(x = col)) +      scale_x_continuous(breaks = seq(min(df[[col]]), max(df[[col]]))) } 

and call

helper(data.frame(x = samp), "x") + geom_bar()