Divides the compositional matrix `x` into the groups defined by `f`.

## Usage

``````# S4 method for class 'CompositionMatrix'
split(x, f, drop = FALSE, ...)

# S4 method for class 'LogRatio'
split(x, f, drop = FALSE, ...)``````

## Arguments

x

A `CompositionMatrix` object.

f

A 'factor' in the sense that `as.factor(f)` defines the grouping, or a list of such factors in which case their interaction is used for the grouping (see `base::split()`).

drop

A `logical` scalar: should levels that do not occur be dropped?

...

Currently not used.

## Value

A `list` of `CompositionMatrix` objects.

Other mutators: `groups`, `samples`, `subset()`, `totals`

N. Frerebeau

## Examples

``````## Create a data.frame
X <- data.frame(
samples = c("A", "A", "A", "B", "B", "B", "C", "C", "C"),
groups = c("X", "X", "X", "X", NA, NA, "Y", "Y", "Y"),
Ca = c(7.72, 7.32, 3.11, 7.19, 7.41, 5, 4.18, 1, 4.51),
Fe = c(6.12, 5.88, 5.12, 6.18, 6.02, 7.14, 5.25, 5.28, 5.72),
Na = c(0.97, 1.59, 1.25, 0.86, 0.76, 0.51, 0.75, 0.52, 0.56)
)

## Coerce to a compositional matrix
Y <- as_composition(X)

## Split by group
split(Y, f = get_groups(Y))
#> \$X
#> <CompositionMatrix: 4 x 3>
#>            Ca        Fe         Na
#> A_1 0.5212694 0.4132343 0.06549629
#> A_2 0.4949290 0.3975659 0.10750507
#> A_3 0.3280591 0.5400844 0.13185654
#> B_1 0.5052706 0.4342937 0.06043570
#>
#> \$Y
#> <CompositionMatrix: 3 x 3>
#>            Ca        Fe         Na
#> C_1 0.4106090 0.5157171 0.07367387
#> C_2 0.1470588 0.7764706 0.07647059
#> C_3 0.4179796 0.5301205 0.05189991
#>

## Split by sample
split(Y, f = get_samples(Y))
#> \$A
#> <CompositionMatrix: 3 x 3>
#>            Ca        Fe         Na
#> A_1 0.5212694 0.4132343 0.06549629
#> A_2 0.4949290 0.3975659 0.10750507
#> A_3 0.3280591 0.5400844 0.13185654
#>
#> \$B
#> <CompositionMatrix: 3 x 3>
#>            Ca        Fe         Na
#> B_1 0.5052706 0.4342937 0.06043570
#> B_2 0.5221987 0.4242424 0.05355884
#> B_3 0.3952569 0.5644269 0.04031621
#>
#> \$C
#> <CompositionMatrix: 3 x 3>
#>            Ca        Fe         Na
#> C_1 0.4106090 0.5157171 0.07367387
#> C_2 0.1470588 0.7764706 0.07647059
#> C_3 0.4179796 0.5301205 0.05189991
#>
``````