R: Examples for 'rlang::exec'

### ** Examples

args <- list(x = c(1:10, 100, NA), na.rm = TRUE)
exec("mean", !!!args)

[1] 14.09091

exec("mean", !!!args, trim = 0.2)

[1] 6

fs <- list(a = function() "a", b = function() "b")
lapply(fs, exec)

$a
[1] "a"

$b
[1] "b"

# Compare to do.call it will not automatically inline expressions
# into the evaluated call.
x <- 10
args <- exprs(x1 = x + 1, x2 = x * 2)
exec(list, !!!args)

$x1
x + 1

$x2
x * 2

do.call(list, args)

$x1
[1] 11

$x2
[1] 20

# exec() is not designed to generate pretty function calls. This is
# most easily seen if you call a function that captures the call:
f <- disp ~ cyl
exec("lm", f, data = mtcars)

Call:
lm(formula = .Primitive("quote")(disp ~ cyl), data = structure(list(
    mpg = c(21, 21, 22.8, 21.4, 18.7, 18.1, 14.3, 24.4, 22.8, 
    19.2, 17.8, 16.4, 17.3, 15.2, 10.4, 10.4, 14.7, 32.4, 30.4, 
    33.9, 21.5, 15.5, 15.2, 13.3, 19.2, 27.3, 26, 30.4, 15.8, 
    19.7, 15, 21.4), cyl = c(6, 6, 4, 6, 8, 6, 8, 4, 4, 6, 6, 
    8, 8, 8, 8, 8, 8, 4, 4, 4, 4, 8, 8, 8, 8, 4, 4, 4, 8, 6, 
    8, 4), disp = c(160, 160, 108, 258, 360, 225, 360, 146.7, 
    140.8, 167.6, 167.6, 275.8, 275.8, 275.8, 472, 460, 440, 
    78.7, 75.7, 71.1, 120.1, 318, 304, 350, 400, 79, 120.3, 95.1, 
    351, 145, 301, 121), hp = c(110, 110, 93, 110, 175, 105, 
    245, 62, 95, 123, 123, 180, 180, 180, 205, 215, 230, 66, 
    52, 65, 97, 150, 150, 245, 175, 66, 91, 113, 264, 175, 335, 
    109), drat = c(3.9, 3.9, 3.85, 3.08, 3.15, 2.76, 3.21, 3.69, 
    3.92, 3.92, 3.92, 3.07, 3.07, 3.07, 2.93, 3, 3.23, 4.08, 
    4.93, 4.22, 3.7, 2.76, 3.15, 3.73, 3.08, 4.08, 4.43, 3.77, 
    4.22, 3.62, 3.54, 4.11), wt = c(2.62, 2.875, 2.32, 3.215, 
    3.44, 3.46, 3.57, 3.19, 3.15, 3.44, 3.44, 4.07, 3.73, 3.78, 
    5.25, 5.424, 5.345, 2.2, 1.615, 1.835, 2.465, 3.52, 3.435, 
    3.84, 3.845, 1.935, 2.14, 1.513, 3.17, 2.77, 3.57, 2.78), 
    qsec = c(16.46, 17.02, 18.61, 19.44, 17.02, 20.22, 15.84, 
    20, 22.9, 18.3, 18.9, 17.4, 17.6, 18, 17.98, 17.82, 17.42, 
    19.47, 18.52, 19.9, 20.01, 16.87, 17.3, 15.41, 17.05, 18.9, 
    16.7, 16.9, 14.5, 15.5, 14.6, 18.6), vs = c(0, 0, 1, 1, 0, 
    1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 
    0, 1, 0, 1, 0, 0, 0, 1), am = c(1, 1, 1, 0, 0, 0, 0, 0, 0, 
    0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 
    1, 1, 1, 1), gear = c(4, 4, 4, 3, 3, 3, 3, 4, 4, 4, 4, 3, 
    3, 3, 3, 3, 3, 4, 4, 4, 3, 3, 3, 3, 3, 4, 5, 5, 5, 5, 5, 
    4), carb = c(4, 4, 1, 1, 2, 1, 4, 2, 2, 4, 4, 3, 3, 3, 4, 
    4, 4, 1, 2, 1, 1, 2, 2, 4, 2, 1, 2, 2, 4, 6, 8, 2)), row.names = c("Mazda RX4", 
"Mazda RX4 Wag", "Datsun 710", "Hornet 4 Drive", "Hornet Sportabout", 
"Valiant", "Duster 360", "Merc 240D", "Merc 230", "Merc 280", 
"Merc 280C", "Merc 450SE", "Merc 450SL", "Merc 450SLC", "Cadillac Fleetwood", 
"Lincoln Continental", "Chrysler Imperial", "Fiat 128", "Honda Civic", 
"Toyota Corolla", "Toyota Corona", "Dodge Challenger", "AMC Javelin", 
"Camaro Z28", "Pontiac Firebird", "Fiat X1-9", "Porsche 914-2", 
"Lotus Europa", "Ford Pantera L", "Ferrari Dino", "Maserati Bora", 
"Volvo 142E"), class = "data.frame"))

Coefficients:
(Intercept)          cyl  
     -156.6         62.6

# If you need finer control over the generated call, you'll need to
# construct it yourself. This may require creating a new environment
# with carefully constructed bindings
data_env <- env(data = mtcars)
eval(expr(lm(!!f, data)), data_env)

Call:
lm(formula = disp ~ cyl, data = data)

Coefficients:
(Intercept)          cyl  
     -156.6         62.6

Examples for 'rlang::exec'

Execute a function