twExtractDim: twExtractDim
In twMisc: Utility functions of tw

Description Usage Arguments Details Value Author(s) See Also Examples

Extract A[...,i,...] from dimension iDim of an array

1	twExtractDim(A, i = 1, iDim = length(dim(A)))

`A`	the array to extract values from
`i`	the index to extract
`iDim`	the dimension to extract from

Sometimes the dimension of an array that is to be processed is only fixed during runtime, i.e. by a value of a variable. However, with standard [,,] extraction the syntax is fixed.

Array functionality of package twMisc

Extract A[...,i,...] from dimension iDim of an array: this method
Splitting an array by dimesnion and listing subarray: twListArrDim
Extracting from last dimensions: twExtractFromLastDims
Stacking a dimension: twStackArrayDim

If the dimensionality of the array is unknown, then the A[,i,] notation is not applicable. This function calculates the indices to extract by using outer.

vector representing the

Thomas Wutzler

twMisc

A <- array( 1:(4*2*3), dim=c(4,2,3) )
str(A)

# extract from last dimension
(tmp1 <- twExtractDim(A,3))
identical( tmp1, A[,,3] ) 

# extract from second dimension
(tmp2 <- twExtractDim(A,2,iDim=2))
identical( tmp2, A[,2,] )

# list all subarrays of last dimension
(tmp3 <- twListArrDim(A))
identical( structure(abind::abind(tmp3,rev.along=0), dimnames=NULL), A )

# list all subarrays of second dimension
(tmp4 <- twListArrDim(A,2))

twExtractFromLastDims(A, 1:2)