Inline version of let
-block.
a %in_block% b
(left argument) named character vector with target names as names, and replacement names as values.
(right argument) expression or block to evaluate under let substitution rules.
evaluated block.
d <- data.frame(
Sepal_Length=c(5.8,5.7),
Sepal_Width=c(4.0,4.4),
Species='setosa')
# let-block notation
let(
qc(
AREA_COL = Sepal_area,
LENGTH_COL = Sepal_Length,
WIDTH_COL = Sepal_Width
),
d %.>%
transform(., AREA_COL = LENGTH_COL * WIDTH_COL)
)
#> Sepal_Length Sepal_Width Species Sepal_area
#> 1 5.8 4.0 setosa 23.20
#> 2 5.7 4.4 setosa 25.08
# %in_block% notation
qc(
AREA_COL = Sepal_area,
LENGTH_COL = Sepal_Length,
WIDTH_COL = Sepal_Width
) %in_block% {
d %.>%
transform(., AREA_COL = LENGTH_COL * WIDTH_COL)
}
#> Sepal_Length Sepal_Width Species Sepal_area
#> 1 5.8 4.0 setosa 23.20
#> 2 5.7 4.4 setosa 25.08
# Note: in packages can make assignment such as:
# AREA_COL <- LENGTH_COL <- WIDTH_COL <- NULL
# prior to code so targets don't look like unbound names.