Imagine I have the following function which has a lot of arguments but for the sake of simplicity I only list two here:
library(glue)
glue("{a} + {b} is equal to 3", a = 1, b = 2)
Now I have a data.table with all the arguments/values that I want to pass to my glue function:
data.table:
library(data.table)
DT <- data.table(varnames = c("a", "b"), values = c(1, 2))
How could I directly pass the arguments/values from my DT onto my glue function?
You can use setNames and call glue_data:
glue_data(setNames(DT$values, DT$varnames), "{a} + {b} is equal to 3")
#1 + 2 is equal to 3
or you use do.call:
do.call(glue, as.list(c("{a} + {b} is equal to 3",
setNames(DT$values, DT$varnames))))
#1 + 2 is equal to 3
It would be helpful in this case if you had a and b as separate columns.
library(data.table)
library(glue)
DT_Wide <- dcast(DT, rowid(varnames)~varnames, value.var = 'values')
DT_Wide
# varnames a b
#1: 1 1 2
Then you can use glue_data -
glue_data(DT_Wide, "{a} + {b} is equal to 3")
#1 + 2 is equal to 3
I would keep it simple and use base R's with as this is the nice example where it is useful:
library(glue)
library(data.table)
DT = data.table(varnames = c("a", "b"), values = c(1, 2))
with(
as.list(setNames(DT$values, DT$varnames)),
glue("{a} + {b} is equal to 3")
)
#1 + 2 is equal to 3
A little hackish but gets the job done and generalises to a bigger data.frame:
DT <- data.table(varnames = c("a", "b", "c"), values = c(1, 2, 3))
DT[, glue_data(
setNames(values, varnames),
glue_data(
.SD,
"{paste(sprintf('{%s}', varnames), collapse = ' + ')}", " is equal to {sum(values)}"
)
)]
# 1 + 2 + 3 is equal to 6
