foldrange: Successively apply a function to a rolling range of a...

In lambda.tools: Tools for Modeling Data with Functional Programming

Description

Apply a function to a rolling range of a sequence and the accumulated value of the previous function applications

Arguments

x	Any indexable data structure
window	The length of the sub-sequence passed to fn
fn	The function applied to the rolling range
acc	An object that stores the intermediate accumulated result

Value

The accumulated result

Usage

foldrange(x, window, fn, acc, idx) foldrange(x, window, fn, acc, 0) foldrange(x, window, fn, acc=0, idx=length(x)-window+1)

When ! is.null(dim(x)) foldrange(x, window, fn, acc=0)

Details

This function is the fold counterpart of maprange. It's primarily here for completeness purposes, as the utility of this function is still to be determined.

Author(s)

Brian Lee Yung Rowe

See Also

map fold foldblock

Examples

## Not run: 
# Mean of rolling means
z <- sapply(1:500, 
  function(x) foldrange(rnorm(50), 10, function(a,b) mean(a) + b) / 41)

## End(Not run)

lambda.tools documentation built on May 2, 2019, 4:28 a.m.