splitAsBumpyMatrix {BumpyMatrix} | R Documentation

## Split to a BumpyMatrix

### Description

Split a vector or Vector into a BumpyMatrix based on row/column factors. This facilitates the construction of a BumpyMatrix from vector-like objects.

### Usage

    splitAsBumpyMatrix(x, row, column, sparse = FALSE)

### Arguments

`x` | A vector or Vector object, most typically a DFrame.
`row` | An object coercible into a factor, of length equal to `x`. This defines the row index for each element of `x`.
`column` | An object coercible into a factor, of length equal to `x`. This defines the column index for each element of `x`.
`sparse` | Logical scalar indicating whether a sparse representation should be used.

### Value

A BumpyMatrix of the appropriate type, with number of rows and columns equal to the number of levels in `row` and `column` respectively. Each entry of the matrix contains all elements of `x` with the corresponding indices in `row` and `column`.

### Author(s)

Aaron Lun

### See Also

`BumpyMatrix`, if a CompressedList has already been constructed.

`unsplitAsDataFrame`, which reverses this operation to recover a long-format DataFrame.

`splitAsList`, which inspired this function.

### Examples

    mat <- splitAsBumpyMatrix(runif(1000),
       row=sample(LETTERS, 1000, replace=TRUE),
       column=sample(10, 1000, replace=TRUE)
    )
    mat
    mat[,1]
    mat[1,]

    # Or with a sparse representation.
    mat <- splitAsBumpyMatrix(runif(10),
       row=sample(LETTERS, 10, replace=TRUE),
       column=sample(10, 10, replace=TRUE)
    )
    mat
    mat[,1]
    mat[1,]

[Package BumpyMatrix version 1.2.0 Index]