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Hop along multiple inputs simultaneously

Source: R/hop2.R, R/phop.R
hop2.Rd

hop2() and phop() represent the combination of slide2() and pslide() with hop(), allowing you to iterate over multiple vectors at once, hopping along them using boundaries defined by .starts and .stops.

Usage

hop2(.x, .y, .starts, .stops, .f, ...)

hop2_vec(.x, .y, .starts, .stops, .f, ..., .ptype = NULL)

phop(.l, .starts, .stops, .f, ...)

phop_vec(.l, .starts, .stops, .f, ..., .ptype = NULL)

Arguments

.x, .y

[vector]

Vectors to iterate over. Vectors of size 1 will be recycled.

.starts, .stops

[integer]

Vectors of boundary locations that make up the windows to bucket .x with. Both .starts and .stops will be recycled to their common size, and that common size will be the size of the result. Both vectors should be integer locations along .x, but out-of-bounds values are allowed.

.f

[function / formula]

If a function, it is used as is.

If a formula, e.g. ~ .x + 2, it is converted to a function. There are three ways to refer to the arguments:

  • For a single argument function, use .

  • For a two argument function, use .x and .y

  • For more arguments, use ..1, ..2, ..3 etc

This syntax allows you to create very compact anonymous functions.

...

Additional arguments passed on to the mapped function.

.ptype

[vector(0) / NULL]

A prototype corresponding to the type of the output.

If NULL, the default, the output type is determined by computing the common type across the results of the calls to .f.

If supplied, the result of each call to .f will be cast to that type, and the final output will have that type.

If getOption("vctrs.no_guessing") is TRUE, the .ptype must be supplied. This is a way to make production code demand fixed types.

.l

[list]

A list of vectors. The length of .l determines the number of arguments that .f will be called with. If .l has names, they will be used as named arguments to .f. Elements of .l with size 1 will be recycled.

Value

A vector fulfilling the following invariants:

hop2()

  • vec_size(hop2(.x, .y, .starts, .stops)) == vec_size_common(.starts, .stops)

  • vec_ptype(hop2(.x, .y, .starts, .stops)) == list()

hop2_vec()

  • vec_size(hop2_vec(.x, .y, .starts, .stops)) == vec_size_common(.starts, .stops)

  • vec_size(hop2_vec(.x, .y, .starts, .stops)[[1]]) == 1L

  • vec_ptype(hop2_vec(.x, .y, .starts, .stops, .ptype = ptype)) == ptype

phop()

  • vec_size(phop(.l, .starts, .stops)) == vec_size_common(.starts, .stops)

  • vec_ptype(phop(.l, .starts, .stops)) == list()

phop_vec()

  • vec_size(phop_vec(.l, .starts, .stops)) == vec_size_common(.starts, .stops)

  • vec_size(phop_vec(.l, .starts, .stops)[[1]]) == 1L

  • vec_ptype(phop_vec(.l, .starts, .stops, .ptype = ptype)) == ptype

See also

hop(), hop_index(), slide2()

Examples

hop2(1:2, 3:4, .starts = 1, .stops = c(2, 1), ~c(x = .x, y = .y))
#> [[1]]
#> x1 x2 y1 y2 
#>  1  2  3  4 
#> 
#> [[2]]
#> x y 
#> 1 3 
#> 

phop(
 list(1, 2:4, 5:7),
 .starts = c(0, 1),
 .stops  = c(2, 4),
 ~c(x = ..1, y = ..2, z = ..3)
)
#> [[1]]
#> x1 x2 y1 y2 z1 z2 
#>  1  1  2  3  5  6 
#> 
#> [[2]]
#> x1 x2 x3 y1 y2 y3 z1 z2 z3 
#>  1  1  1  2  3  4  5  6  7 
#>