defunct
Please consider using the slider package.
Fixing an initial window and expanding more observations:
stretch() always returns a list.
stretch_lgl(), stretch_int(), stretch_dbl(), stretch_chr() use the same
arguments as stretch(), but return vectors of the corresponding type.
stretch_dfr() stretch_dfc() return data frames using row-binding & column-binding.
stretch(.x, .f, ..., .step = 1, .init = 1, .fill = NA, .bind = FALSE)stretch_dfr(
.x,
.f,
...,
.step = 1,
.init = 1,
.fill = NA,
.bind = FALSE,
.id = NULL
)
stretch_dfc(.x, .f, ..., .step = 1, .init = 1, .fill = NA, .bind = FALSE)
An object to slide over.
A function, formula, or vector (not necessarily atomic).
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.
If character vector, numeric vector, or list, it is
converted to an extractor function. Character vectors index by
name and numeric vectors index by position; use a list to index
by position and name at different levels. If a component is not
present, the value of .default will be returned.
Additional arguments passed on to the mapped function.
A positive integer for incremental step.
A positive integer for an initial window size.
A value to fill at the left/center/right of the data range depending
on .align (NA by default). NULL means no filling.
If .x is a list, should .x be combined before applying .f?
If .x is a list of data frames, row binding is carried out.
Either a string or NULL. If a string, the output will contain
a variable with that name, storing either the name (if .x is named) or
the index (if .x is unnamed) of the input. If NULL, the default, no
variable will be created.
Only applies to _dfr variant.
if .fill != NULL, it always returns the same length as input.
Other stretching window functions:
stretch2()