r - Call to ggplot in a function with NSE -

the idea patch call ggplot in function.

the example:

library(dplyr) library(ggplot2) library(lazyeval)  df <- data.frame(a=letters[1:10], b=2:11, c=3:12))  func <- function(name, dat=df) {    output <- dat %>%     select_(~a,name) %>%     arrange_(interp(~desc(var), var=as.name(name)))    plot <-      ggplot(output, aes_string(x=reorder(~a,-name), y=b)) +     geom_bar(stat='identity')    print(plot)   return(plot)  }  result <- func("b") 

compiling gives:

error in -name : invalid argument unary operator.

i tried deparse , substitute. not sure got right combo. ideas?

reorder data before passing ggplot. following code moves of column names around in ggplot call, because otherwise you’d plotting a against b, regardless of name argument — or intentional?

function (dat, name) {     var = as.name(name)     reord = list(interp(~ reorder(var, -var), var = var))     output = dat %>%         select_(~a, name) %>% # not necessary.         arrange_(interp(~ desc(var), var = var)) %>%         mutate_(.dots = setnames(reord, name))      plot = ggplot(output, aes_string(x = 'a', y = name)) +         geom_bar(stat = 'identity')      plot(plot)     plot }  func(df, 'b') 

i’m using mutate_(.dots = …) form here. have @ dplyr’s “nse” vignette more information on usage.