Capture current evaluation context.

This function captures the current context, making it easier to use **ply with functions that do special evaluation and need access to the environment where ddply was called from.

here(f)

Arguments

f

a function that does non-standard evaluation

Author

Peter Meilstrup, https://github.com/crowding

Examples

df <- data.frame(a = rep(c("a","b"), each = 10), b = 1:20)
f1 <- function(label) {
   ddply(df, "a", mutate, label = paste(label, b))
}
if (FALSE) f1("name:") # \dontrun{}
# Doesn't work because mutate can't find label in the current scope

f2 <- function(label) {
   ddply(df, "a", here(mutate), label = paste(label, b))
}
f2("name:")
#>    a  b    label
#> 1  a  1  name: 1
#> 2  a  2  name: 2
#> 3  a  3  name: 3
#> 4  a  4  name: 4
#> 5  a  5  name: 5
#> 6  a  6  name: 6
#> 7  a  7  name: 7
#> 8  a  8  name: 8
#> 9  a  9  name: 9
#> 10 a 10 name: 10
#> 11 b 11 name: 11
#> 12 b 12 name: 12
#> 13 b 13 name: 13
#> 14 b 14 name: 14
#> 15 b 15 name: 15
#> 16 b 16 name: 16
#> 17 b 17 name: 17
#> 18 b 18 name: 18
#> 19 b 19 name: 19
#> 20 b 20 name: 20
# Works :)