itertools (version 0.1-3)

iarray: Create an iterator over an array

Description

Create an iterator over an array.

Usage

iarray(X, MARGIN, ..., chunks, chunkSize, drop, idx=lapply(dim(X), function(i) TRUE))

Arguments

X

Array to iterate over.

MARGIN

Vector of subscripts to iterate over. Note that if the length of MARGIN is greater than one, the resulting iterator will generate iterators which is particularly useful with nested foreach loops.

...

Used to force subsequent arguments to be specified by name.

chunks

Number of elements that the iterator should generate. This can be a single value or a vector the same length as MARGIN. A single value will be recycled for each dimension if MARGIN has more than one value.

chunkSize

The maximum size Number of elements that the iterator should generate. This can be a single value or a vector the same length as MARGIN. A single value will be recycled for each dimension if MARGIN has more than one value.

drop

Should dimensions of length 1 be dropped in the generated values? It defaults to FALSE if either chunks or chunkSize is specified, otherwise to TRUE.

idx

List of indices used to generate a call object.

See Also

apply

Examples

  # Iterate over matrices in a 3D array
  x <- array(1:24, c(2,3,4))
  as.list(iarray(x, 3))

  # Iterate over subarrays
  as.list(iarray(x, 3, chunks=2))

  x <- array(1:64, c(4,4,4))
  it <- iarray(x, c(2,3), chunks=c(1,2))
  jt <- nextElem(it)
  nextElem(jt)
  jt <- nextElem(it)
  nextElem(jt)

  it <- iarray(x, c(2,3), chunks=c(2,2))
  jt <- nextElem(it)
  nextElem(jt)
  nextElem(jt)
  jt <- nextElem(it)
  nextElem(jt)
  nextElem(jt)