Apply This By Every n Values — this_by

Applies a function by every n values to a vector.

this_by_n(invec, n = 3, FUN = sum, fill = NA, include_first = TRUE)

Arguments

invec	The input vector.
n	By how many values?
FUN	The function to apply to each set of n values.
fill	The value to padd the resulting vector with. Defaults to `NA`.
include_first	Logical. Should the first value be included. Defaults to `TRUE`.

Value

A vector the same length as the input vector.

References

http://stackoverflow.com/q/34563693/1270695

Author

Ananda Mahto

Examples


x <- c(1, 2, 3, 4, 7, 9, 2, 4)
this_by_n(x, 3, mean)
#> [1] 2.000000 3.000000 4.666667 6.666667 6.000000 5.000000 3.000000 4.000000
this_by_n(x, 2, max)
#> [1] 2 3 4 7 9 9 4 4
this_by_n(x, 4, min)
#> [1] 1 2 3 2 2 2 2 4
this_by_n(letters[1:10], 5, toString)
#>  [1] "a, b, c, d, e" "b, c, d, e, f" "c, d, e, f, g" "d, e, f, g, h"
#>  [5] "e, f, g, h, i" "f, g, h, i, j" "g, h, i, j"    "h, i, j"      
#>  [9] "i, j"          "j"