Quick note on quo, enquo, and {{var}} commands when using a function that calls a dataframe in R. For Hadley’s documentation, see this website, or this one.
Here is the data.
| id | others | pressure | performance |
|---|---|---|---|
| 1 | 0 | 0 | 6.134445 |
| 1 | 0 | 1 | 8.956932 |
| 1 | 0 | 2 | 8.435113 |
| 1 | 1 | 0 | 13.820419 |
| 1 | 1 | 1 | 15.473562 |
| 1 | 1 | 2 | 5.466076 |
| 1 | 2 | 0 | 10.331524 |
| 1 | 2 | 1 | 7.717611 |
| 1 | 2 | 2 | 7.990309 |
| 2 | 0 | 0 | 10.823559 |
| 2 | 0 | 1 | 6.930184 |
| 2 | 0 | 2 | 4.541806 |
| 2 | 1 | 0 | 7.996631 |
| 2 | 1 | 1 | 9.822106 |
| 2 | 1 | 2 | 12.640498 |
| 2 | 2 | 0 | 10.805539 |
| 2 | 2 | 1 | 9.941262 |
| 2 | 2 | 2 | 8.425159 |
| 3 | 0 | 0 | 5.772006 |
| 3 | 0 | 1 | 4.498032 |
| 3 | 0 | 2 | 9.525057 |
| 3 | 1 | 0 | 12.263280 |
| 3 | 1 | 1 | 7.263611 |
| 3 | 1 | 2 | 12.399793 |
| 3 | 2 | 0 | 14.471659 |
| 3 | 2 | 1 | 6.710794 |
| 3 | 2 | 2 | 8.397338 |
I want to take the commands below
ggplot(df %>% filter(pressure == 0), aes(x = as.factor(others), y = performance)) +
geom_violin(trim = F) +
theme_classic() +
xlab("Others Watching") +
ylab("Performance") +
theme(axis.text.y = element_blank(),
axis.ticks.y = element_blank()) +
ggtitle("Pressure = 0")
and create a function. Here it is:
boxfunc <- function(col, title){
col <- enquo(col)
# use !! here
ggplot(df %>% filter(pressure == !!col), aes(x = as.factor(others), y = performance)) +
geom_violin(trim = F) +
theme_classic() +
xlab("Others Watching") +
ylab("Performance") +
theme(axis.text.y = element_blank(),
axis.ticks.y = element_blank()) +
# use parameter here
ggtitle(paste("Pressure =", title, sep = " "))
}
Now use it.
boxfunc(0, 1)
boxfunc(1, 2)
Note that I can’t use boxfunc(quo(0),1) because R functions can’t handle a quo alongside a second parameter. Instead, I had to use enquo within the function.
You could also use a {{var}} approach:
varfunc <- function(col, title){
# use {{var}} here
ggplot(df %>% filter(pressure == {{col}}), aes(x = as.factor(others), y = performance)) +
geom_violin(trim = F) +
theme_classic() +
xlab("Others Watching") +
ylab("Performance") +
theme(axis.text.y = element_blank(),
axis.ticks.y = element_blank()) +
# use parameter here
ggtitle(paste("Pressure =", title, sep = " "))
}
varfunc(0, 1)
Bo\(^2\)m =)