问题
How do I use highcharter::hchart inside a function?
Here is a simple line graph using the hchart
function.
library(tidyverse)
library(lubridate)
library(highcharter)
library(nycflights13)
flights_2 <- flights %>%
mutate(dep_mo = ymd(str_c(year, month, "01", sep = "-"))) %>%
group_by(dep_mo) %>%
summarize(arr_delay = mean(arr_delay, na.rm = TRUE))
hchart(flights_2,
type = "line",
hcaes(x = dep_mo, y = arr_delay),
name = "Average Arrival Delay")
When I try to write a function to create the same graph I get an error.
h_fun <- function(df, x, y) {
hchart(df,
type = "line",
hcaes(x = x, y = y),
name = "Average Arrival Delay"
)
}
h_fun(df = flights_2, x = dep_mo, y = arr_delay)
This is the error message: Error in mutate_impl(.data, dots) : Binding not found: x.
When I traceback the error it seems hchart
is using dplyr::mutate_
. This leads me to believe the error has something to do with NSE and maybe hchart
needs something akin to ggplot2::aes_string()
(link). However, I can't find any documentation on a similar function in highcharter
.
回答1:
We need to use enquo()
& quo_name()
together with hcaes_string
enquo()
captures the expression supplied as argument by the user & returns a quosure.quo_name()
squashes the quosure and transforms it into a string.
Watch Hadley explained tidyeval
in this 5min video if you haven't heard about it. More on tidyeval
here
library(tidyverse)
library(lubridate)
library(highcharter)
library(nycflights13)
flights_2 <- flights %>%
mutate(dep_mo = ymd(str_c(year, month, "01", sep = "-"))) %>%
group_by(dep_mo) %>%
summarize(arr_delay = mean(arr_delay, na.rm = TRUE))
h_fun2 <- function(df, x, y) {
x <- enquo(x)
y <- enquo(y)
hchart(df,
type = "line",
hcaes_string(quo_name(x), quo_name(y)),
name = "Average Arrival Delay"
)
}
h_fun2(df = flights_2, x = dep_mo, y = arr_delay)
Edit: as of April 18, 2018, the development version of highcharter
supports tidyeval
so h_fun2
can be rewritten as:
h_fun2 <- function(df, x, y) {
x <- enexpr(x)
y <- enexpr(y)
hchart(df,
type = "line",
hcaes(!!x, !!y),
name = "Average Arrival Delay"
)
}
来源:https://stackoverflow.com/questions/49263587/use-highcharter-inside-a-function