Keeps rows/columns in an array-like object using a predicate function.

## Usage

```
keep(x, ...)
keep_cols(x, ...)
keep_rows(x, ...)
# S4 method for ANY
keep(
x,
f,
margin = 1,
negate = FALSE,
all = FALSE,
verbose = getOption("arkhe.verbose"),
...
)
# S4 method for ANY
keep_rows(
x,
f,
negate = FALSE,
all = FALSE,
verbose = getOption("arkhe.verbose"),
...
)
# S4 method for ANY
keep_cols(
x,
f,
negate = FALSE,
all = FALSE,
verbose = getOption("arkhe.verbose"),
...
)
```

## Arguments

- x
An R object (should be a

`matrix`

or a`data.frame`

).- ...
Further arguments to be passed to

`f`

.- f
A predicate

`function`

.- margin
A length-one

`numeric`

vector giving the subscripts which the function will be applied over (`1`

indicates rows,`2`

indicates columns).- negate
A

`logical`

scalar: should the negation of`f`

be used instead of`f`

?- all
A

`logical`

scalar. If`TRUE`

, only the rows/columns whose values all meet the condition defined by`f`

are considered. If`FALSE`

(the default), only rows/columns where at least one value validates the condition defined by`f`

are considered.- verbose
A

`logical`

scalar: should R report extra information on progress?

## Examples

```
## Create a data matrix
X <- matrix(sample(1:10, 25, TRUE), nrow = 5, ncol = 5)
## Add NA
k <- sample(1:25, 3, FALSE)
X[k] <- NA
X
#> [,1] [,2] [,3] [,4] [,5]
#> [1,] 2 5 10 6 2
#> [2,] NA 6 2 2 NA
#> [3,] 6 3 4 8 4
#> [4,] 3 5 3 6 2
#> [5,] 3 NA 10 9 10
## Keep row without any NA
keep(X, f = is.na, margin = 1, negate = TRUE, all = TRUE)
#> [,1] [,2] [,3] [,4] [,5]
#> [1,] 2 5 10 6 2
#> [2,] 6 3 4 8 4
#> [3,] 3 5 3 6 2
## Keep row without any NA
keep(X, f = is.na, margin = 2, negate = TRUE, all = TRUE)
#> [,1] [,2]
#> [1,] 10 6
#> [2,] 2 2
#> [3,] 4 8
#> [4,] 3 6
#> [5,] 10 9
```