How to user NSE inside fct_reorder() in ggplot2 - r

Question

I would like to know how to use NSE (Non-Standard Evaluation) expression in fct_reorder() in ggplot2 to replicate charts for different data frames.
This is an example of data frame that I use to draw a chart:
travel_time_br30 travel_time_br30_int time_reduction shift not_shift total
1 0-30 0 10 2780 3268 6048
2 0-30 0 20 2779 3269 6048
3 0-30 0 30 2984 3064 6048
4 0-30 0 40 3211 2837 6048
5 30-60 30 10 2139 2007 4146
6 30-60 30 20 2159 1987 4146
7 30-60 30 30 2363 1783 4146
8 30-60 30 40 2478 1668 4146
9 60-90 60 10 764 658 1422
10 60-90 60 20 721 701 1422
11 60-90 60 30 782 640 1422
12 60-90 60 40 801 621 1422
13 90-120 90 10 296 224 520
14 90-120 90 20 302 218 520
15 90-120 90 30 317 203 520
16 90-120 90 40 314 206 520
17 120-150 120 10 12 10 22
18 120-150 120 20 10 12 22
19 120-150 120 30 10 12 22
20 120-150 120 40 13 9 22
21 150-180 150 10 35 21 56
22 150-180 150 20 40 16 56
23 150-180 150 30 40 16 56
24 150-180 150 40 35 21 56
share
1 45.96561
2 45.94907
3 49.33862
4 53.09193
5 51.59190
6 52.07429
7 56.99469
8 59.76845
9 53.72714
10 50.70323
11 54.99297
12 56.32911
13 56.92308
14 58.07692
15 60.96154
16 60.38462
17 54.54545
18 45.45455
19 45.45455
20 59.09091
21 62.50000
22 71.42857
23 71.42857
24 62.50000
These are the scripts to draw a chart from above data frame:
g.var <- "travel_time_br30"
go.var <- "travel_time_br30_int"
test %>% ggplot(.,aes_(x=as.name(x.var),y=as.name("share"),group=as.name(g.var))) +
geom_line(size=1.4, aes(
color=fct_reorder(travel_time_br30,order(travel_time_br30_int))))
As I have several data frames which has different fields such as access_time_br30, access_time_br30_int instead of travel_time_br30 and travel_time_br30_int in the data frame, I set two variables (g.var and go.var) to easily replicate multiple chars in the same scripts.
As I need to reorder the factor group numerically, in particular, changing order of travel_time_br30 by travel_time_br30_int, I am using fct_reorder function in ggplot2(., aes_(...)). However, if I use aes_ with fct_reorder() in geom_line() as shown as an example in the following script, it returns an error saying Error:fmust be a factor (or character vector).
geom_line(size=1.4, aes_(color=fct_reorder(as.name(g.var),order(as.name(go.var)))))
Fct_reorder() does not seem to have an NSE version like fct_reorder_().
Is it impossible to use both aes_ and fct_reorder() in a sequence of scripts or are there any other solutions?

Answer 1

Based on my novice working knowledge of tidy-eval, you could transform your factor order in mutate() before passing the data into ggplot() and acheive your result.
Sorry I couldn't easily read in your table above, because of the line return so I made a new example off of mtcars that I think captures your intent. (let me know if it doesn't)
mtcars2 <- mutate(mtcars,
gear_int = 6 - gear,
gear_intrev = rev(gear_int)) %>%
mutate_at(vars(cyl, gear), as.factor)
library(rlang)
gg_reorder <- function(data, col_var, col_order) {
eq_var <- sym(col_var) # sym is flexible and my novice preference
eq_ord <- sym(col_order)
data %>% mutate(!!quo_name(eq_var) := fct_reorder(!!eq_var, !!eq_ord) ) %>%
ggplot(aes_(~mpg, ~hp, color = eq_var)) +
geom_line()
}
And now put it to use plotting...
gg_reorder(mtcars2, "gear", "gear_int")
gg_reorder(mtcars2, "gear", "gear_intrev")
I didn't specify all of the aes_() variables as strings but you could pass those as text and use the as.name() pattern. If you want more tidy-eval patterns Edwin Thoen wrote up a bunch of common cases.